Updated the final file and source and zip

But not fixed the find failed issue yet
Find failed have only one record found, but it's many

.gitignore

@@ -0,0 +1,4 @@
+*.bin
+
+.idea
+*.out

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "files.associations": {
+        "typeinfo": "c"
+    }
+}

README.md

@@ -1,4 +1,6 @@
-# SBN C Assigement
+# SBN C-Assigement
 
 - [ ] Student Details
-- [ ] ...
+- [ ] Linked List
+- [ ] Book Data Store
+- [ ] Etc.

data/students.test.txt

@@ -0,0 +1,40 @@
+Jon
+1101825
+Computer
+4
+88
+98
+52
+95
+Sambo
+12345
+CS90
+2
+50
+40
+Chea
+6789
+CS78
+2
+50
+20
+SMC1
+7890
+CGS
+4
+40
+50
+60
+70
+CHS10
+7823
+CHS2
+2
+19
+90
+CMS
+345
+SDC
+2
+1
+4

data/test.txt

@@ -0,0 +1,4 @@
+hey, how are you?
+i'm fine. thank you!
+then what you think?
+nothing!

final/README.md

@@ -0,0 +1,6 @@
+### Guide
+#### Compile
+```shell
+gcc q1.c -o q1
+./q1
+```

final/q1.c

@@ -0,0 +1,598 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+
+#define BUFFER_SIZE 128
+#define MAX_NO_OF_UNITS 4
+#define NAME_SIZE 20
+
+const char *FILE_STUDENT_DATA_PATH = "./students.txt";
+
+struct person_tag
+{
+    char name[20];
+    char id[10];
+};
+
+struct course_tag
+{
+    char course_name[20];
+    int no_of_units;
+    int marks[MAX_NO_OF_UNITS];
+    float avg;
+};
+
+struct student_tag
+{
+    struct person_tag student_info;
+    struct course_tag course_info;
+    struct student_tag *next;
+} * head;
+
+// typedef for declared to use as data type
+typedef struct person_tag PERSON;
+typedef struct course_tag COURSE;
+typedef struct student_tag STUDENT;
+
+// file function
+void read_file();
+
+// util functions
+int menu();
+void print_welcome();
+void print_student(STUDENT *student);
+void release(STUDENT *data);
+int find_min_in_array(int *array);
+STUDENT *search_student_by_name_or_id(char search_key[NAME_SIZE]);
+STUDENT *find_maximum_avg();
+STUDENT *add_last_student(STUDENT *nodes, STUDENT *element);
+
+// core functions
+void display_students();
+void search_student();
+void find_maximum();
+void find_failed();
+void update_file();
+void quite();
+
+// Linked list functions
+void add_student(char student_name[20], char student_id[10], char course_name[20], int no_of_units, int marks[MAX_NO_OF_UNITS]);
+int count_elements(STUDENT *elements);
+int count();
+
+int main(void)
+{
+    // variable use for menu selected
+    int selected;
+
+    print_welcome();
+
+    // init the read data from the file
+    read_file();
+
+    while (1)
+    {
+        selected = menu();
+
+        switch (selected)
+        {
+        case 1:
+            display_students();
+            break;
+        case 2:
+            search_student();
+            break;
+        case 3:
+            find_maximum();
+            break;
+        case 4:
+            find_failed();
+            break;
+        case 5:
+            update_file();
+            break;
+        case 6:
+            quite();
+            break;
+        default:
+            printf("cannot find your option!");
+            break;
+        }
+    }
+}
+
+void print_welcome()
+{
+    printf("Welcome!\n");
+}
+
+void display_students()
+{
+    read_file();
+
+    STUDENT *student = head;
+
+    if (student == NULL)
+    {
+        printf("\nNo student!\n");
+        return;
+    }
+
+    print_student(student);
+}
+
+void print_student(STUDENT *student)
+{
+    int records_count = 0;
+    printf("\n================ Student Details ================\n");
+    while (student != NULL)
+    {
+        printf("\n");
+        printf("Student Name: %s\n", student->student_info.name);
+        printf("Student ID: %s\n", student->student_info.id);
+        printf("Course Name: %s\n", student->course_info.course_name);
+        printf("No of units: %d\n", student->course_info.no_of_units);
+
+        printf("Marks: [ ");
+        for (int i = 0; i < student->course_info.no_of_units; i++)
+        {
+            printf("%d ", student->course_info.marks[i]);
+        }
+        printf("]\n");
+        printf("Avg: %.2f\n", student->course_info.avg);
+        student = student->next;
+        records_count++;
+    }
+
+    // output the records count
+    printf("\nRecords: %d has been loaded successfully!\n", records_count);
+
+    // clean up the memory
+    // after output the data
+    // because we don;t need it anymore after output
+    release(student);
+}
+
+int menu()
+{
+    printf("\n(1) Display students’ details\n");
+    printf("(2) Search for a student’s mark\n");
+    printf("(3) Find the details of student with the largest average\n");
+    printf("(4) Find the details of failed students\n");
+    printf("(5) Add new student to the record\n");
+    printf("(6) Quit program\n");
+
+    int choosen;
+    printf("\nEnter your option: ");
+    scanf("%d", &choosen);
+    return choosen;
+}
+
+void add_student(char student_name[20], char student_id[10], char course_name[20], int no_of_units, int marks[MAX_NO_OF_UNITS])
+{
+    STUDENT *temp, *iterator;
+    temp = (struct student_tag *)malloc(sizeof(struct student_tag));
+    PERSON info;
+    memcpy(info.name, student_name, 20);
+    memcpy(info.id, student_id, 10);
+
+    COURSE course;
+    memcpy(course.course_name, course_name, 20);
+    course.no_of_units = no_of_units;
+    // memcpy(course.marks, marks);
+
+    float sum = 0;
+    for (int i = 0; i < no_of_units; i++)
+    {
+        course.marks[i] = marks[i];
+        sum += marks[i];
+    }
+    course.avg = sum / no_of_units;
+    temp->student_info = info;
+    temp->course_info = course;
+
+    // reference in head
+    iterator = head;
+
+    if (head == NULL)
+    {
+        head = temp;
+        head->next = NULL;
+    }
+    else
+    {
+        while (iterator->next != NULL)
+        {
+            iterator = iterator->next;
+        }
+        temp->next = NULL;
+        iterator->next = temp;
+    }
+}
+
+int count_elements(STUDENT *elements)
+{
+    int n = 1;
+    STUDENT *temp;
+    temp = elements;
+    if (head == NULL)
+    {
+        return 0;
+    }
+
+    while (temp->next != NULL)
+    {
+        n++;
+        temp = temp->next;
+    }
+
+    return n;
+}
+
+int count()
+{
+    return count_elements(head);
+}
+
+void search_student()
+{
+    char search_key[NAME_SIZE];
+
+    printf("Enter student name or id to search: ");
+    scanf("%s", &search_key);
+
+    STUDENT *found_student = search_student_by_name_or_id(search_key);
+    if (found_student == NULL)
+    {
+        printf("\nNo student found!\n");
+        return;
+    }
+
+    print_student(found_student);
+}
+
+STUDENT *search_student_by_name_or_id(char search_key[NAME_SIZE])
+{
+    // refresh data from file first
+    read_file();
+
+    STUDENT *temp = head;
+
+    while (temp != NULL)
+    {
+        if (strcmp(temp->student_info.name, search_key) == 0 || strcmp(temp->student_info.id, search_key) == 0)
+        {
+            printf("\nSearch found with key: %s\n", search_key);
+            // set the temp next to null
+            // and free up the memory
+            temp->next = NULL;
+            free(temp->next);
+
+            // return the current temp
+            // that found in current search
+            return temp;
+        }
+        temp = temp->next;
+    }
+
+    return NULL;
+}
+
+STUDENT *find_maximum_avg()
+{
+    // refresh data from file first
+    read_file();
+
+    STUDENT *temp = head, *max;
+    max = temp->next;
+
+    while (temp != NULL)
+    {
+        if (max == NULL)
+        {
+            return temp;
+        }
+
+        if (max->course_info.avg < temp->course_info.avg)
+        {
+            max = temp;
+        }
+
+        temp = temp->next;
+    }
+
+    // release the max next record
+    // set max next element to NULL
+    // because we use only one record
+    release(max->next);
+    max->next = NULL;
+
+    return max;
+}
+
+int find_min_in_array(int *array)
+{
+    if (array == NULL)
+    {
+        return -1;
+    }
+
+    int min = array[0];
+    size_t size = sizeof(array) / sizeof(array[0]);
+
+    for (int i = 1; i < size; i++)
+    {
+        if (array[i] < min)
+        {
+            min = array[i];
+        }
+    }
+    return min;
+}
+
+STUDENT *add_last_student(STUDENT *nodes, STUDENT *element)
+{
+    STUDENT *temp = nodes, *node;
+    node = (struct student_tag *)malloc(sizeof(struct student_tag));
+    node->student_info = element->student_info;
+    node->course_info = element->course_info;
+    node->next = NULL;
+
+    if (nodes == NULL)
+    {
+        nodes = node;
+
+        return nodes;
+    }
+
+    // store current as tempo
+    // ref for nodes
+    temp = nodes;
+
+    while (temp->next != NULL)
+    {
+        temp = temp->next;
+    }
+
+    temp->next = node;
+
+    return nodes;
+}
+
+// ISSUE: can't find all failed students
+// It's just return one record back
+STUDENT *find_failed_mark(int upper_mark)
+{
+    // refresh data from file first
+    read_file();
+
+    printf("Count elements: %d\n", count());
+
+    STUDENT *temp = head, *failed_students = NULL;
+
+    int count = count_elements(temp);
+    printf("Temp count elements: %d", count);
+
+    int run_count = 0;
+
+    while (temp != NULL)
+    {
+        run_count++;
+
+        int min = find_min_in_array(temp->course_info.marks);
+        if (min < upper_mark)
+        {
+            printf("\nRun min: %d\n", min);
+            failed_students = add_last_student(failed_students, temp);
+        }
+
+        temp = temp->next;
+    }
+
+    printf("\nRun count: %d", run_count);
+
+    return failed_students;
+}
+
+void find_maximum()
+{
+    // refresh data from file first
+    read_file();
+
+    STUDENT *max_student = find_maximum_avg();
+    if (max_student == NULL)
+    {
+        printf("\nNo maximum student found!\n");
+        return;
+    }
+
+    printf("\nFind maximum avg was found with: %0.2f\n", max_student->course_info.avg);
+    print_student(max_student);
+}
+
+void find_failed()
+{
+    int upper_mark = 50;
+    STUDENT *failed_students = find_failed_mark(upper_mark);
+    if (failed_students == NULL)
+    {
+        printf("\nNo failed student found!\n");
+        return;
+    }
+
+    printf("\nFind the failed students that at least one mark less than %d\n", upper_mark);
+    print_student(failed_students);
+}
+
+void update_file()
+{
+    FILE *file;
+    file = fopen(FILE_STUDENT_DATA_PATH, "a");
+
+    char name[20];
+    char id[10];
+    char course_name[20];
+    int no_of_units;
+    int marks[MAX_NO_OF_UNITS];
+
+    printf("Enter student name: ");
+    scanf("%s", &name);
+
+    printf("Enter student id: ");
+    scanf("%s", &id);
+
+    printf("Enter course name: ");
+    scanf("%s", &course_name);
+
+again:
+    printf("Enter no of units: ");
+    scanf("%d", &no_of_units);
+
+    if (no_of_units > MAX_NO_OF_UNITS && no_of_units <= 0)
+    {
+        printf("\nyou cannot input the units bigger than %d or less than 0\n", MAX_NO_OF_UNITS);
+        getchar();
+        goto again;
+    }
+
+    for (int i = 0; i < no_of_units; i++)
+    {
+        printf("Enter mark[%d]: ", i + 1);
+        scanf("%d", &marks[i]);
+    }
+
+    if (count() > 0)
+    {
+        fputs("\n", file);
+    }
+
+    fputs(name, file);
+    fputs("\n", file);
+    fputs(id, file);
+    fputs("\n", file);
+    fputs(course_name, file);
+    fputs("\n", file);
+    fprintf(file, "%d", no_of_units);
+
+    for (int i = 0; i < no_of_units; i++)
+    {
+        fputs("\n", file);
+        fprintf(file, "%d", marks[i]);
+    }
+
+    fclose(file);
+
+    printf("\nRecord saved successfully!\n");
+
+    // reload data into linked list again
+    // read_file();
+
+    // show back the all results
+    display_students();
+}
+
+void read_file()
+{
+    // release nodes
+    // we need to clean up the memory
+    if (head != NULL)
+    {
+        STUDENT *temp;
+        while (head != NULL)
+        {
+            temp = head;
+            head = head->next;
+            free(temp);
+        }
+    }
+
+    FILE *file;
+    file = fopen(FILE_STUDENT_DATA_PATH, "r");
+
+    if (file == NULL)
+    {
+        printf("cannot read file: %s", FILE_STUDENT_DATA_PATH);
+        exit(EXIT_FAILURE);
+    }
+
+    char student_name[20];
+    char student_id[10];
+    char course_name[20];
+    int no_of_units;
+    int marks[4];
+
+    int i;
+    while (!feof(file))
+    {
+        char no[BUFFER_SIZE];
+
+        fgets(student_name, sizeof student_name, file);
+        fgets(student_id, sizeof student_id, file);
+        fgets(course_name, sizeof course_name, file);
+        fgets(no, sizeof no, file);
+
+        i = 0;
+        while (student_name[i] != '\n')
+        {
+            i++;
+        }
+
+        student_name[i] = '\0';
+
+        i = 0;
+        while (student_id[i] != '\n')
+        {
+            i++;
+        }
+
+        student_id[i] = '\0';
+
+        i = 0;
+        while (course_name[i] != '\n')
+        {
+            i++;
+        }
+
+        course_name[i] = '\0';
+
+        no_of_units = atoi(no);
+        for (int j = 0; j < no_of_units; j++)
+        {
+            char mark[BUFFER_SIZE];
+
+            fgets(mark, sizeof mark, file);
+            sscanf(mark, "%d", &marks[j]);
+        }
+
+        // add into linked list
+        add_student(student_name, student_id, course_name, no_of_units, marks);
+    }
+
+    fclose(file);
+}
+
+void quite()
+{
+    printf("\nGoodbye!");
+    exit(EXIT_SUCCESS);
+}
+
+void release(STUDENT *data)
+{
+    if (data == NULL)
+    {
+        return;
+    }
+
+    // free the nodes
+    // because it can be use in memory
+    // we need to clear it first
+    // before we re-initailize the new data
+    STUDENT *temp;
+    while (data != NULL)
+    {
+        temp = data;
+        data = data->next;
+        free(temp);
+    }
+}

final/q2.c

@@ -0,0 +1,79 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+
+#define STUDENT_ID_SIZE 10
+#define CHAR_INT '0'
+
+struct studentID
+{
+    int value;
+    struct studentID *next;
+};
+
+typedef struct studentID STUDENTID;
+typedef STUDENTID *STUDENTIDPtr;
+
+int main()
+{
+
+    const char student_id[] = "1001245345";
+
+    // 1. creation nodes
+    size_t student_id_len = sizeof(student_id) / sizeof(student_id[0]) - 1;
+
+    STUDENTIDPtr student_ptr_1 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_2 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_3 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_4 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_5 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+
+    student_ptr_1->next = student_ptr_2;
+    student_ptr_2->next = student_ptr_3;
+    student_ptr_3->next = student_ptr_4;
+    student_ptr_4->next = student_ptr_5;
+    student_ptr_5->next = NULL;
+
+    // 2. fill the node's values
+    STUDENTIDPtr temp = student_ptr_1;
+    int last_len = 5;
+    while (temp != NULL)
+    {
+        temp->value = student_id[student_id_len - last_len] - CHAR_INT;
+        temp = temp->next;
+        last_len--;
+    }
+
+    // 3. removes dup
+    STUDENTIDPtr temp1, temp2, duplicate;
+    temp1 = student_ptr_1;
+
+    while (temp1 != NULL && temp1->next != NULL)
+    {
+        temp2 = temp1;
+
+        while (temp2->next != NULL)
+        {
+            if (temp1->value == temp2->next->value)
+            {
+                duplicate = temp2->next;
+                temp2->next = temp2->next->next;
+                free(duplicate);
+            }
+            else
+                temp2 = temp2->next;
+        }
+        temp1 = temp1->next;
+    }
+
+    // output the result
+    while (student_ptr_1 != NULL)
+    {
+        printf("%d ", student_ptr_1->value);
+        student_ptr_1 = student_ptr_1->next;
+    }
+
+    printf("\n");
+
+    return EXIT_SUCCESS;
+}

final/q3.c

@@ -0,0 +1,286 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+#include "time.h"
+
+#define DEPOT_SIZE 10
+
+struct Bus
+{
+    int BusID;
+    int RouteID;
+    time_t schedule;
+} Depot[DEPOT_SIZE];
+
+typedef enum
+{
+    true,
+    false
+} bool;
+
+void createBuses();
+void printBuses();
+void scheduleBuses();
+void alignupBuses();
+void releaseBuses();
+void emergency();
+
+// utils variable
+bool has_created = false;
+bool has_scheduled = false;
+bool has_aligned = false;
+int top = -1;
+
+// utils function
+void clrscr();
+void print_depot(struct Bus *depot);
+
+time_t get_random_time();
+
+void confirm_on_finish();
+int quicksort_compare_func(const void *elem1, const void *elem2);
+bool isEmpty();
+int menu();
+
+void remove_index_of_array(int index);
+
+// Main Function
+int main()
+{
+    while (1)
+    {
+        int selection = menu();
+        clrscr();
+        printf("You Select : %d", selection);
+        printf("\n");
+
+        switch (selection)
+        {
+        case 1:
+            createBuses();
+            break;
+        case 2:
+            printBuses();
+            break;
+
+        case 3:
+            scheduleBuses();
+            break;
+        case 4:
+            alignupBuses();
+            break;
+
+        case 5:
+            releaseBuses();
+            break;
+
+        case 6:
+            emergency();
+            break;
+
+        default:
+            printf("You are enter incorrect option number");
+        }
+
+        confirm_on_finish();
+    };
+
+    return EXIT_SUCCESS;
+}
+
+int menu()
+{
+    fflush(stdout);
+
+    clrscr();
+
+    printf("\nQuestion 3 ");
+    printf("\n=========================================");
+    printf("\n");
+    printf("\n1. Create Buses");
+    printf("\n2. Print Buses");
+    printf("\n3. Schedule Buses");
+    printf("\n4. Align up Buses");
+    printf("\n5. Release Buses");
+    printf("\n6. Emergency Buses");
+
+    int chosen;
+    printf("\n\nEnter Your Selection : ");
+    scanf("%d", &chosen);
+    return chosen;
+}
+
+void createBuses()
+{
+
+    if (has_created == true)
+    {
+        printf("\nYou have created already...");
+        return;
+    }
+
+    printf("\n\nStart Create Buses...");
+
+    for (int i = 0; i < DEPOT_SIZE; i++)
+    {
+        top++;
+        Depot[i].BusID = i + 1;
+        Depot[i].RouteID = 1000 + (i + i);
+        printf("\n - Starting Create Bus %d", i + 1);
+    }
+
+    has_created = true;
+
+    printf("\nFinish Created Buses");
+}
+
+void printBuses()
+{
+    if (has_created == false)
+    {
+        printf("\nPlease Create Buses First!");
+        return;
+    }
+    print_depot(Depot);
+}
+
+void scheduleBuses()
+{
+    if (has_created == false)
+    {
+        printf("\nPlease Create Buses First!");
+        return;
+    }
+
+    printf("\nStart Scheduling Buses...\n\n");
+
+    size_t currentLen = sizeof(Depot) / sizeof(Depot[0]);
+
+    for (int i = 0; i < currentLen; i++)
+    {
+        printf("\n  - Start Random Schedule %d...", i);
+
+        Depot[i].schedule = get_random_time();
+    }
+
+    printf("\n\nEnd Scheduling Buses...");
+
+    has_scheduled = true;
+}
+
+void print_depot(struct Bus *depot)
+{
+
+    size_t currentLen = sizeof(Depot) / sizeof(*Depot);
+
+    for (int i = 0; i < top; i++)
+    {
+        printf("Bus ID: %d\n", depot[i].BusID);
+        printf("Route ID: %d\n", depot[i].RouteID);
+
+        char *scheduleForShow = "";
+        if (depot[i].schedule != 0)
+        {
+            scheduleForShow = ctime(&depot[i].schedule);
+        }
+
+        printf("Schdule Time : %s\n\n", scheduleForShow);
+    }
+}
+
+void alignupBuses()
+{
+    if (has_scheduled == false)
+    {
+        printf("\n\nYou are not scheduling buses yet ...");
+        return;
+    }
+    size_t currentLen = sizeof(Depot) / sizeof(Depot[0]);
+
+    qsort(Depot, sizeof(Depot) / sizeof(*Depot), sizeof(*Depot), quicksort_compare_func);
+
+    printf("\n\nFinish Align up Buses Schedule ... ");
+    has_aligned = true;
+}
+
+void releaseBuses()
+{
+    if (has_aligned == false)
+    {
+        printf("\n\nYou are not align buses schedule yet ...");
+        return;
+    }
+
+    int last_index = sizeof(Depot) / sizeof(*Depot) - 1;
+
+    remove_index_of_array(last_index);
+
+    printf("\n\nRelease Complete...\n\n");
+}
+
+void emergency()
+{
+    if (has_aligned == false)
+    {
+        printf("\n\nYou are not align buses schedule yet ...");
+        return;
+    }
+
+    remove_index_of_array(0);
+
+    printf("\n\nRelease Complete...\n\n");
+}
+
+void remove_index_of_array(int remove_index)
+{
+
+    int current_len = sizeof(Depot) / sizeof(*Depot);
+    memmove(Depot + remove_index, Depot + remove_index + 1, (sizeof(Depot) - remove_index - 1) * sizeof(*Depot));
+    top--;
+}
+
+time_t get_random_time()
+{
+    time_t currentTime;
+
+    time(&currentTime);
+
+    long currentTimeNumber = (long)localtime(&currentTime);
+
+    // Random in next 5 hours
+    long randomAddOnTime = rand() % (60 * 60 * 5);
+
+    long additionTime = currentTimeNumber + randomAddOnTime;
+
+    return additionTime;
+}
+
+void clrscr()
+{
+    system("clear");
+}
+
+void confirm_on_finish()
+{
+
+    printf("\n\nPress Enter to Back to Menu...");
+
+    getchar();
+    getchar();
+}
+
+bool isFull()
+{
+    return top == -1;
+}
+
+int quicksort_compare_func(const void *elem1, const void *elem2)
+{
+    struct Bus element1 = *((struct Bus *)elem1);
+    struct Bus element2 = *((struct Bus *)elem2);
+    if (element1.schedule > element2.schedule)
+        return -1;
+    if (element1.schedule < element2.schedule)
+        return 1;
+    return 0;
+}

final/students.txt

@@ -0,0 +1,37 @@
+Jon
+1101825
+Computer
+4
+88
+98
+52
+95
+Peter
+112152
+Electrical
+3
+67
+40
+59
+Mary
+1201925
+Mechanical
+4
+78
+55
+79
+75
+Sherin
+1201925
+Civil
+4
+69
+53
+34
+88
+Jose
+34567
+Software
+2
+34
+56

run

@@ -1,6 +1,10 @@
 #!/bin/bash
 
-echo "compile the program.c file..."
-gcc work1/main.c -o program
-echo "run the program..."
-./program
+# echo "compile the program.c file..."
+# gcc work1/main.c -o program
+# echo "run the program..."
+# ./program
+
+rm -r single.bin
+
+gcc work1/q3.c -o single.bin && ./single.bin

runBook

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+gcc tests/bookNode.c -o bookNode.bin && ./bookNode.bin

tests/bookNode.c

@@ -0,0 +1,238 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+struct book
+{
+    char *title;
+    char *author;
+    char *isbn;
+    struct book *next;
+};
+
+typedef struct book BOOK;
+
+FILE *file;
+BOOK *head;
+
+void add_book(char *title, char *author, char *isbn);
+void display();
+int count();
+void add_book_data();
+void save_book_data(struct book *data);
+void read_file_to_data();
+void print_data(BOOK *data);
+
+int main()
+{
+    head = NULL;
+
+    int countEntries = count();
+    printf("There are %d entries\n", countEntries);
+
+    // add book data
+    add_book_data();
+
+    // display the books
+    display();
+
+    return EXIT_SUCCESS;
+}
+
+void add_book(char *title, char *author, char *isbn)
+{
+    struct book *temp, *iterator;
+    temp = (struct book *)malloc(sizeof(struct book));
+    temp->title = title;
+    temp->author = author;
+    temp->isbn = isbn;
+    // ref
+    iterator = head;
+
+    if (head == NULL)
+    {
+        head = temp;
+        head->next = NULL;
+    }
+    else
+    {
+        while (iterator->next != NULL)
+        {
+            iterator = iterator->next;
+        }
+        temp->next = NULL;
+        iterator->next = temp;
+    }
+}
+
+int count()
+{
+    int n = 1;
+    BOOK *temp;
+    temp = head;
+    if (head == NULL)
+    {
+        return 0;
+    }
+
+    while (temp->next != NULL)
+    {
+        n++;
+        temp = temp->next;
+    }
+
+    return n;
+}
+
+void add_book_data()
+{
+    add_book("My Third Book", "Zero 1", "000-000-111");
+    add_book("My Fouth Book", "1 Zero", "111-000-000");
+    add_book("My Fifth Book", "2 Zero", "222-000-000");
+
+    int i;
+    file = fopen("./data/books.txt", "a+");
+
+    if (file == NULL)
+    {
+        printf("Error: addressbook.dat could not be opened.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    BOOK *temp;
+    temp = head;
+
+    fputs(temp->title, file);
+    fputs("\n", file);
+    fputs(temp->author, file);
+    fputs("\n", file);
+    fputs(temp->isbn, file);
+
+    while (temp->next != NULL)
+    {
+        temp = temp->next;
+        fputs("\n", file);
+        fputs(temp->title, file);
+        fputs("\n", file);
+        fputs(temp->author, file);
+        fputs("\n", file);
+        fputs(temp->isbn, file);
+    }
+
+    // close the file
+    fclose(file);
+}
+
+void save_book_data(struct book *data)
+{
+    file = fopen("./data/books.txt", "a+");
+
+    if (file == NULL)
+    {
+        printf("Error: addressbook.dat could not be opened.\n");
+        exit(EXIT_FAILURE);
+    }
+
+    BOOK *temp;
+    temp = data;
+
+    if (temp == NULL)
+    {
+        return;
+    }
+
+    fputs(temp->title, file);
+    fputs(temp->author, file);
+    fputs(temp->isbn, file);
+
+    while (temp->next != NULL)
+    {
+        temp = temp->next;
+
+        fputs(temp->title, file);
+        fputs(temp->author, file);
+        fputs(temp->isbn, file);
+    }
+
+    fflush(file);
+    fclose(file);
+}
+
+void read_file_to_data()
+{
+    // clear head in linked list
+    head = NULL;
+
+    FILE *file;
+
+    file = fopen("./data/books.txt", "r");
+
+    if (file == NULL)
+    {
+        printf("cannot read file!");
+        exit(EXIT_FAILURE);
+    }
+
+    char title[20];
+    char author[20];
+    char isbn[20];
+    int i;
+
+    while (!feof(file))
+    {
+        fgets(title, 20, file);
+        fgets(author, 20, file);
+        fgets(isbn, 20, file);
+
+        i = 0;
+
+        while (title[i] != '\n')
+        {
+            i++;
+        }
+
+        title[i] = '\0';
+
+        i = 0;
+
+        while (author[i] != '\n')
+        {
+            i++;
+        }
+
+        author[i] = '\0';
+
+        add_book(title, author, isbn);
+    }
+
+    fclose(file);
+}
+
+void display()
+{
+    read_file_to_data();
+    print_data(head);
+}
+
+void print_data(BOOK *book)
+{
+    BOOK *temp;
+    temp = book;
+    if (temp == NULL)
+    {
+        printf("book is empty!");
+        return;
+    }
+
+    printf("Book title: %s\n", temp->title);
+    printf("Book author: %s\n", temp->author);
+    printf("Book isbn: %s", temp->isbn);
+
+    while (temp->next != NULL)
+    {
+        temp = temp->next;
+        printf("\n\n============ %s ============\n", temp->title);
+        printf("Book title: %s\n", temp->title);
+        printf("Book author: %s\n", temp->author);
+        printf("Book isbn: %s", temp->isbn);
+    }
+}

tests/linkedlist.c

@@ -0,0 +1,225 @@
+#include "stdio.h"
+#include "stdlib.h"
+
+struct node
+{
+    int data;
+    struct node *next;
+};
+
+struct node *head = NULL;
+void add_first(int);
+void add_last(int);
+void traverse();
+void remove_first();
+void remove_last();
+int count = 0;
+void display_menu();
+
+int main(void)
+{
+    printf("Welcome!\n");
+
+    int selected, data;
+
+    while (1)
+    {
+        printf("\n");
+
+        // show menu
+        display_menu();
+
+        printf("Enter your option: ");
+        scanf("%d", &selected);
+
+        if (selected == 1)
+        {
+            printf("Enter you element to add first: ");
+            scanf("%d", &data);
+            add_first(data);
+        }
+        else if (selected == 2)
+        {
+            printf("Enter you element to add last: ");
+            scanf("%d", &data);
+            add_last(data);
+        }
+        else if (selected == 3)
+        {
+            traverse();
+        }
+        else if (selected == 4)
+        {
+            remove_first;
+        }
+        else if (selected == 5)
+        {
+            remove_last();
+        }
+        else
+        {
+            printf("\nGoodbye!");
+            exit(EXIT_SUCCESS);
+        }
+    }
+    return 0;
+}
+
+void display_menu()
+{
+    printf("1. Add first element\n");
+    printf("2. Add last element\n");
+    printf("3. Traverse element\n");
+    printf("4. Remove first element\n");
+    printf("5. Remove last element\n");
+    printf("Any to quite program\n");
+}
+
+void add_first(int element)
+{
+    // init node
+    struct node *node;
+
+    // allocate the node for linkedlist
+    node = (struct node *)malloc(sizeof(struct node));
+
+    // add the data into node
+    node->data = element;
+
+    // count the nodes, that added into data
+    count++;
+
+    // check the head, if null put the data into it
+    if (head == NULL)
+    {
+        // replace the node into head
+        head = node;
+
+        // set the next of head into null
+        head->next = NULL;
+
+        printf("Element %d has been added into the first!", element);
+
+        // return or end this process
+        return;
+    }
+
+    // put the first element of the head
+    // because we need the old head into the next of new head
+    node->next = head;
+
+    // replace the head node from current node
+    head = node;
+
+    printf("Element %d has been added into the first!", element);
+}
+
+void add_last(int element)
+{
+    struct node *node, *temp;
+
+    node = (struct node *)malloc(sizeof(struct node));
+    node->data = element;
+    count++;
+
+    if (head == NULL)
+    {
+        head = node;
+        head->next = NULL;
+
+        printf("Element %d has been add into first/last!\n", element);
+        return;
+    }
+
+    // store current as tempo
+    temp = head;
+
+    while (temp->next != NULL)
+    {
+        temp = temp->next;
+    }
+
+    temp->next = node;
+    node->next = NULL;
+    head = temp;
+}
+
+void traverse()
+{
+    struct node *node;
+
+    node = head;
+
+    if (node == NULL)
+    {
+        printf("Linked list is empty!\n");
+        return;
+    }
+
+    printf("Total elements count: %d in linked list.\n", count);
+
+    while (node->next != NULL)
+    {
+        printf("%d\n", node->data);
+        node = node->next;
+    }
+
+    printf("%d\n", node->data);
+}
+
+void remove_first()
+{
+    struct node *node;
+    int data;
+
+    if (head == NULL)
+    {
+        printf("No elements found!\n");
+        return;
+    }
+
+    data = head->data;
+    node = head->next;
+    free(head);
+    head = node;
+    count--;
+
+    printf("Element %d has been removed from first!\n", data);
+}
+
+void remove_last()
+{
+    struct node *node, *temp;
+    int data;
+
+    if (head == NULL)
+    {
+        printf("No elements found!\n");
+        return;
+    }
+
+    count--;
+
+    if (head->next == NULL)
+    {
+        data = head->data;
+        free(head);
+        head = NULL;
+        printf("Element %d has been removed from last!\n");
+        return;
+    }
+
+    node = head;
+
+    while (node->next != NULL)
+    {
+        temp = node;
+        node = node->next;
+    }
+
+    data = node->data;
+    temp->next = NULL;
+    free(node);
+
+    printf("Element %d has been removed from last!\n");
+}

tests/readFileFromText.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct list
+{
+    char *text;
+    struct list *next;
+};
+
+typedef struct list LIST;
+
+int main(void)
+{
+    FILE *file;
+    char line[128];
+    LIST *current, *head;
+
+    head = current = NULL;
+    file = fopen("./data/test.txt", "r");
+
+    while (fgets(line, sizeof(line), file))
+    {
+        LIST *node = malloc(sizeof(LIST));
+        node->text = strdup(line);
+        node->next = NULL;
+
+        if (head == NULL)
+        {
+            current = head = node;
+        }
+        else
+        {
+            current = current->next = node;
+        }
+    }
+
+    // close the file
+    fclose(file);
+
+    for (current = head; current; current = current->next)
+    {
+        printf("%s", current->text);
+    }
+
+    return 0;
+}

tests/run

@@ -1,4 +1,4 @@
 #!/bin/bash
 
-gcc work1.c -o work1
-./work1
+rm -r work1.bin
+gcc work1.c -o work1.bin && ./work1.bin

tests/runLinkedlist

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+rm -r linkedlist
+
+gcc linkedlist.c -o linkedlist
+
+./linkedlist

tests/test1.c

@@ -0,0 +1,25 @@
+#include "stdio.h"
+#include "stdlib.h"
+
+struct person {
+    char name[20];
+    int age;
+};
+
+struct student {
+    int id;
+    struct person info;
+    struct student *next;
+};
+
+void add_first();
+void add_last();
+void remove_first();
+void remove_last();
+void show();
+void quite();
+
+int main() {
+
+    printf("Goodbye!");
+}

tests/util.c

@@ -0,0 +1,17 @@
+#include "stdio.h"
+
+void print(char *text)
+{
+    printf(text);
+}
+
+void println(char *text)
+{
+    newline();
+    print(text);
+}
+
+void newline()
+{
+    printf("\n");
+}

tests/work1.c

@@ -1,6 +1,7 @@
 #include "stdio.h"
 #include "string.h"
 #include "stdlib.h"
+#include "util.c"
 
 struct person_tag
 {
@@ -25,7 +26,7 @@ struct student_tag
 
 int main()
 {
-
+    int selected;
     struct person_tag person, person2 = {"Chea", "4567892"}, *personPtr;
 
     // strcpy style
@@ -56,16 +57,26 @@ int main()
     printf("Course name: %s \n", first->course_info.course_name);
     printf("Course of units: %d", first->course_info.no_of_units);
 
+    read_file("./../data/welcome.txt");
+
+    display_menu();
+
+    newline();
+
+    // scanf("\nenter the option: ", selected);
+
+    // menu(selected);
+
     return 0;
 }
 
-void read_file()
+void read_file(char *filename)
 {
     // read the file here...
     FILE *file;
     char c;
 
-    if ((file = fopen("./../data/welcome.txt", "r")) == NULL)
+    if ((file = fopen(filename, "r")) == NULL)
     {
         printf("no file were found...!");
     }
@@ -80,7 +91,6 @@ void read_file()
 
 void menu(int menu)
 {
-    // do something here...
     switch (menu)
     {
     case 1:
@@ -92,3 +102,34 @@ void menu(int menu)
         break;
     }
 }
+
+void display_menu()
+{
+    printf("\n");
+    read_file("./../note/section1.txt");
+}
+
+void display_students()
+{
+}
+
+void search_student()
+{
+}
+
+void find_maximum()
+{
+}
+
+void find_failed()
+{
+}
+
+void update_file()
+{
+}
+
+void exit_program()
+{
+    println("Goodbye...");
+}

work1/function.c

@@ -2,26 +2,32 @@
 #include "stdio.h"
 #include "./student_tag.h"
 
-void display() {
+void display()
+{
     printf("display...");
 }
 
-void search(int mark) {
+void search(int mark)
+{
     printf("search mark...");
 }
 
-void find_largest_average() {
+void find_largest_average()
+{
     printf("find largest average...");
 }
 
-void find_failed_students() {
+void find_failed_students()
+{
     printf("find failed students...");
 }
 
-void add_new(struct student_tag student) {
+void add_new(struct student_tag student)
+{
     printf("add new...");
 }
 
-void quite() {
+void quite()
+{
     exit(1);
 }

work1/main.c

@@ -32,5 +32,4 @@ int main()
 
     // show menu
     menu();
-
 }

work1/menu.c

@@ -15,8 +15,6 @@ void menu()
     printf("\n(6) Quit program\n\n");
 }
 
-
-
 void choose_menu(int menu)
 {
 
@@ -35,8 +33,8 @@ void choose_menu(int menu)
         find_failed_students();
         break;
     case MENU_5:
-    
-        struct person_tag info = {"1","Sambo"};
+
+        struct person_tag info = {"1", "Sambo"};
         struct student_tag std = {.student_info = info};
         add_new(std);
         break;

work1/q1.c

@@ -0,0 +1,597 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+
+#define BUFFER_SIZE 128
+#define MAX_NO_OF_UNITS 4
+#define NAME_SIZE 20
+
+const char *FILE_STUDENT_DATA_PATH = "./data/students.test.txt";
+
+struct person_tag
+{
+    char name[20];
+    char id[10];
+};
+
+struct course_tag
+{
+    char course_name[20];
+    int no_of_units;
+    int marks[MAX_NO_OF_UNITS];
+    float avg;
+};
+
+struct student_tag
+{
+    struct person_tag student_info;
+    struct course_tag course_info;
+    struct student_tag *next;
+} * head;
+
+// typedef for declared to use as data type
+typedef struct person_tag PERSON;
+typedef struct course_tag COURSE;
+typedef struct student_tag STUDENT;
+
+// file function
+void read_file();
+
+// util functions
+int menu();
+void print_welcome();
+void print_student(STUDENT *student);
+void release(STUDENT *data);
+int find_min_in_array(int *array);
+STUDENT *search_student_by_name_or_id(char search_key[NAME_SIZE]);
+STUDENT *find_maximum_avg();
+STUDENT *add_last_student(STUDENT *nodes, STUDENT *element);
+
+// core functions
+void display_students();
+void search_student();
+void find_maximum();
+void find_failed();
+void update_file();
+void quite();
+
+// Linked list functions
+void add_student(char student_name[20], char student_id[10], char course_name[20], int no_of_units, int marks[MAX_NO_OF_UNITS]);
+int count_elements(STUDENT *elements);
+int count();
+
+int main(void)
+{
+    // variable use for menu selected
+    int selected;
+
+    print_welcome();
+
+    // init the read data from the file
+    read_file();
+
+    while (1)
+    {
+        selected = menu();
+
+        switch (selected)
+        {
+        case 1:
+            display_students();
+            break;
+        case 2:
+            search_student();
+            break;
+        case 3:
+            find_maximum();
+            break;
+        case 4:
+            find_failed();
+            break;
+        case 5:
+            update_file();
+            break;
+        case 6:
+            quite();
+            break;
+        default:
+            printf("cannot find your option!");
+            break;
+        }
+    }
+}
+
+void print_welcome()
+{
+    printf("Welcome!\n");
+}
+
+void display_students()
+{
+    read_file();
+
+    STUDENT *student = head;
+
+    if (student == NULL)
+    {
+        printf("\nNo student!\n");
+        return;
+    }
+
+    print_student(student);
+}
+
+void print_student(STUDENT *student)
+{
+    int records_count = 0;
+    printf("\n================ Student Details ================\n");
+    while (student != NULL)
+    {
+        printf("\n");
+        printf("Student Name: %s\n", student->student_info.name);
+        printf("Student ID: %s\n", student->student_info.id);
+        printf("Course Name: %s\n", student->course_info.course_name);
+        printf("No of units: %d\n", student->course_info.no_of_units);
+
+        printf("Marks: [ ");
+        for (int i = 0; i < student->course_info.no_of_units; i++)
+        {
+            printf("%d ", student->course_info.marks[i]);
+        }
+        printf("]\n");
+        printf("Avg: %.2f\n", student->course_info.avg);
+        student = student->next;
+        records_count++;
+    }
+
+    // output the records count
+    printf("\nRecords: %d has been loaded successfully!\n", records_count);
+
+    // clean up the memory
+    // after output the data
+    // because we don;t need it anymore after output
+    release(student);
+}
+
+int menu()
+{
+    printf("\n(1) Display students’ details\n");
+    printf("(2) Search for a student’s mark\n");
+    printf("(3) Find the details of student with the largest average\n");
+    printf("(4) Find the details of failed students\n");
+    printf("(5) Add new student to the record\n");
+    printf("(6) Quit program\n");
+
+    int choosen;
+    printf("\nEnter your option: ");
+    scanf("%d", &choosen);
+    return choosen;
+}
+
+void add_student(char student_name[20], char student_id[10], char course_name[20], int no_of_units, int marks[MAX_NO_OF_UNITS])
+{
+    STUDENT *temp, *iterator;
+    temp = (struct student_tag *)malloc(sizeof(struct student_tag));
+    PERSON info;
+    memcpy(info.name, student_name, 20);
+    memcpy(info.id, student_id, 10);
+
+    COURSE course;
+    memcpy(course.course_name, course_name, 20);
+    course.no_of_units = no_of_units;
+    // memcpy(course.marks, marks);
+
+    float sum = 0;
+    for (int i = 0; i < no_of_units; i++)
+    {
+        course.marks[i] = marks[i];
+        sum += marks[i];
+    }
+    course.avg = sum / no_of_units;
+    temp->student_info = info;
+    temp->course_info = course;
+
+    // reference in head
+    iterator = head;
+
+    if (head == NULL)
+    {
+        head = temp;
+        head->next = NULL;
+    }
+    else
+    {
+        while (iterator->next != NULL)
+        {
+            iterator = iterator->next;
+        }
+        temp->next = NULL;
+        iterator->next = temp;
+    }
+}
+
+int count_elements(STUDENT *elements)
+{
+    int n = 1;
+    STUDENT *temp;
+    temp = elements;
+    if (head == NULL)
+    {
+        return 0;
+    }
+
+    while (temp->next != NULL)
+    {
+        n++;
+        temp = temp->next;
+    }
+
+    return n;
+}
+
+int count()
+{
+    return count_elements(head);
+}
+
+void search_student()
+{
+    char search_key[NAME_SIZE];
+
+    printf("Enter student name or id to search: ");
+    scanf("%s", &search_key);
+
+    STUDENT *found_student = search_student_by_name_or_id(search_key);
+    if (found_student == NULL)
+    {
+        printf("\nNo student found!\n");
+        return;
+    }
+
+    print_student(found_student);
+}
+
+STUDENT *search_student_by_name_or_id(char search_key[NAME_SIZE])
+{
+    // refresh data from file first
+    read_file();
+
+    STUDENT *temp = head;
+
+    while (temp != NULL)
+    {
+        if (strcmp(temp->student_info.name, search_key) == 0 || strcmp(temp->student_info.id, search_key) == 0)
+        {
+            printf("\nSearch found with key: %s\n", search_key);
+            // set the temp next to null
+            // and free up the memory
+            temp->next = NULL;
+            free(temp->next);
+
+            // return the current temp
+            // that found in current search
+            return temp;
+        }
+        temp = temp->next;
+    }
+
+    return NULL;
+}
+
+STUDENT *find_maximum_avg()
+{
+    // refresh data from file first
+    read_file();
+
+    STUDENT *temp = head, *max;
+    max = temp->next;
+
+    while (temp != NULL)
+    {
+        if (max == NULL)
+        {
+            return temp;
+        }
+
+        if (max->course_info.avg < temp->course_info.avg)
+        {
+            max = temp;
+        }
+
+        temp = temp->next;
+    }
+
+    // release the max next record
+    // set max next element to NULL
+    // because we use only one record
+    release(max->next);
+    max->next = NULL;
+
+    return max;
+}
+
+int find_min_in_array(int *array)
+{
+    if (array == NULL)
+    {
+        return -1;
+    }
+
+    int min = array[0];
+    size_t size = sizeof(array) / sizeof(array[0]);
+
+    for (int i = 1; i < size; i++)
+    {
+        if (array[i] < min)
+        {
+            min = array[i];
+        }
+    }
+    return min;
+}
+
+STUDENT *add_last_student(STUDENT *nodes, STUDENT *element)
+{
+    STUDENT *temp = nodes, *node;
+    node = (struct student_tag *)malloc(sizeof(struct student_tag));
+    node->student_info = element->student_info;
+    node->course_info = element->course_info;
+    node->next = NULL;
+
+    if (nodes == NULL)
+    {
+        nodes = node;
+
+        return nodes;
+    }
+
+    // store current as tempo
+    // ref for nodes
+    temp = nodes;
+
+    while (temp->next != NULL)
+    {
+        temp = temp->next;
+    }
+
+    temp->next = node;
+
+    return nodes;
+}
+
+// ISSUE: can't find all failed students
+// It's just return one record back
+STUDENT *find_failed_mark(int upper_mark)
+{
+    // refresh data from file first
+    read_file();
+
+    printf("Count elements: %d\n", count());
+
+    STUDENT *temp = head, *failed_students = NULL;
+
+    int count = count_elements(temp);
+    printf("Temp count elements: %d", count);
+
+    int run_count = 0;
+
+    while (temp != NULL)
+    {
+        run_count++;
+
+        int min = find_min_in_array(temp->course_info.marks);
+        if (min < upper_mark)
+        {
+            printf("\nRun min: %d\n", min);
+            failed_students = add_last_student(failed_students, temp);
+        }
+
+        temp = temp->next;
+    }
+
+    printf("\nRun count: %d", run_count);
+
+    return failed_students;
+}
+
+void find_maximum()
+{
+    // refresh data from file first
+    read_file();
+
+    STUDENT *max_student = find_maximum_avg();
+    if (max_student == NULL)
+    {
+        printf("\nNo maximum student found!\n");
+        return;
+    }
+
+    printf("\nFind maximum avg was found with: %0.2f\n", max_student->course_info.avg);
+    print_student(max_student);
+}
+
+void find_failed()
+{
+    int upper_mark = 50;
+    STUDENT *failed_students = find_failed_mark(upper_mark);
+    if (failed_students == NULL)
+    {
+        printf("\nNo failed student found!\n");
+        return;
+    }
+
+    printf("\nFind the failed students that at least one mark less than %d\n", upper_mark);
+    print_student(failed_students);
+}
+
+void update_file()
+{
+    FILE *file;
+    file = fopen(FILE_STUDENT_DATA_PATH, "a");
+
+    char name[20];
+    char id[10];
+    char course_name[20];
+    int no_of_units;
+    int marks[MAX_NO_OF_UNITS];
+
+    printf("Enter student name: ");
+    scanf("%s", &name);
+
+    printf("Enter student id: ");
+    scanf("%s", &id);
+
+    printf("Enter course name: ");
+    scanf("%s", &course_name);
+
+again:
+    printf("Enter no of units: ");
+    scanf("%d", &no_of_units);
+
+    if (no_of_units > MAX_NO_OF_UNITS && no_of_units <= 0)
+    {
+        printf("\nyou cannot input the units bigger than %d or less than 0\n", MAX_NO_OF_UNITS);
+        getchar();
+        goto again;
+    }
+
+    for (int i = 0; i < no_of_units; i++)
+    {
+        printf("Enter mark[%d]: ", i + 1);
+        scanf("%d", &marks[i]);
+    }
+
+    if (count() > 0)
+    {
+        fputs("\n", file);
+    }
+
+    fputs(name, file);
+    fputs("\n", file);
+    fputs(id, file);
+    fputs("\n", file);
+    fputs(course_name, file);
+    fputs("\n", file);
+    fprintf(file, "%d", no_of_units);
+
+    for (int i = 0; i < no_of_units; i++)
+    {
+        fputs("\n", file);
+        fprintf(file, "%d", marks[i]);
+    }
+
+    fclose(file);
+
+    printf("\nRecord saved successfully!\n");
+
+    // reload data into linked list again
+    // read_file();
+
+    display_students();
+}
+
+void read_file()
+{
+    // release nodes
+    // we need to clean up the memory
+    if (head != NULL)
+    {
+        STUDENT *temp;
+        while (head != NULL)
+        {
+            temp = head;
+            head = head->next;
+            free(temp);
+        }
+    }
+
+    FILE *file;
+    file = fopen(FILE_STUDENT_DATA_PATH, "r");
+
+    if (file == NULL)
+    {
+        printf("cannot read file: %s", FILE_STUDENT_DATA_PATH);
+        exit(EXIT_FAILURE);
+    }
+
+    char student_name[20];
+    char student_id[10];
+    char course_name[20];
+    int no_of_units;
+    int marks[4];
+
+    int i;
+    while (!feof(file))
+    {
+        char no[BUFFER_SIZE];
+
+        fgets(student_name, sizeof student_name, file);
+        fgets(student_id, sizeof student_id, file);
+        fgets(course_name, sizeof course_name, file);
+        fgets(no, sizeof no, file);
+
+        i = 0;
+        while (student_name[i] != '\n')
+        {
+            i++;
+        }
+
+        student_name[i] = '\0';
+
+        i = 0;
+        while (student_id[i] != '\n')
+        {
+            i++;
+        }
+
+        student_id[i] = '\0';
+
+        i = 0;
+        while (course_name[i] != '\n')
+        {
+            i++;
+        }
+
+        course_name[i] = '\0';
+
+        no_of_units = atoi(no);
+        for (int j = 0; j < no_of_units; j++)
+        {
+            char mark[BUFFER_SIZE];
+
+            fgets(mark, sizeof mark, file);
+            sscanf(mark, "%d", &marks[j]);
+        }
+
+        // add into linked list
+        add_student(student_name, student_id, course_name, no_of_units, marks);
+    }
+
+    fclose(file);
+}
+
+void quite()
+{
+    printf("\nGoodbye!");
+    exit(EXIT_SUCCESS);
+}
+
+void release(STUDENT *data)
+{
+    if (data == NULL)
+    {
+        return;
+    }
+
+    // free the nodes
+    // because it can be use in memory
+    // we need to clear it first
+    // before we re-initailize the new data
+    STUDENT *temp;
+    while (data != NULL)
+    {
+        temp = data;
+        data = data->next;
+        free(temp);
+    }
+}

work1/q2.c

@@ -0,0 +1,83 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+
+#define STUDENT_ID_SIZE 10
+#define CHAR_INT '0'
+
+struct studentID
+{
+    int value;
+    struct studentID *next;
+};
+
+typedef struct studentID STUDENTID;
+typedef STUDENTID *STUDENTIDPtr;
+
+int main()
+{
+
+    const char student_id[] = "1001245345";
+
+    // printf("Student ID: %s\n", student_id);
+
+    // memcpy(five_digits, &student_id[5], 5);
+    // five_digits[5] = '\0';
+
+    // creation nodes
+    size_t student_id_len = sizeof(student_id) / sizeof(student_id[0]) - 1;
+
+    STUDENTIDPtr student_ptr_1 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_2 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_3 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_4 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+    STUDENTIDPtr student_ptr_5 = (STUDENTIDPtr)malloc(sizeof(STUDENTID));
+
+    student_ptr_1->next = student_ptr_2;
+    student_ptr_2->next = student_ptr_3;
+    student_ptr_3->next = student_ptr_4;
+    student_ptr_4->next = student_ptr_5;
+    student_ptr_5->next = NULL;
+
+    // fill the node's values
+    STUDENTIDPtr temp = student_ptr_1;
+    int last_len = 5;
+    while (temp != NULL)
+    {
+        temp->value = student_id[student_id_len - last_len] - CHAR_INT;
+        temp = temp->next;
+        last_len--;
+    }
+
+    // removes dup
+    STUDENTIDPtr temp1, temp2, duplicate;
+    temp1 = student_ptr_1;
+
+    while (temp1 != NULL && temp1->next != NULL)
+    {
+        temp2 = temp1;
+
+        while (temp2->next != NULL)
+        {
+            if (temp1->value == temp2->next->value)
+            {
+                duplicate = temp2->next;
+                temp2->next = temp2->next->next;
+                free(duplicate);
+            }
+            else
+                temp2 = temp2->next;
+        }
+        temp1 = temp1->next;
+    }
+
+    while (student_ptr_1 != NULL)
+    {
+        printf("%d ", student_ptr_1->value);
+        student_ptr_1 = student_ptr_1->next;
+    }
+
+    printf("\n");
+
+    return EXIT_SUCCESS;
+}

work1/q3.c

@@ -0,0 +1,286 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+#include "time.h"
+
+#define DEPOT_SIZE 10
+
+struct Bus
+{
+    int BusID;
+    int RouteID;
+    time_t schedule;
+} Depot[DEPOT_SIZE];
+
+typedef enum
+{
+    true,
+    false
+} bool;
+
+void createBuses();
+void printBuses();
+void scheduleBuses();
+void alignupBuses();
+void releaseBuses();
+void emergency();
+
+// utils variable
+bool has_created = false;
+bool has_scheduled = false;
+bool has_aligned = false;
+int top = -1;
+
+// utils function
+void clrscr();
+void print_depot(struct Bus *depot);
+
+time_t get_random_time();
+
+void confirm_on_finish();
+int quicksort_compare_func(const void *elem1, const void *elem2);
+bool isEmpty();
+int menu();
+
+void remove_index_of_array(int index);
+
+// Main Function
+int main()
+{
+    while (1)
+    {
+        int selection = menu();
+        clrscr();
+        printf("You Select : %d", selection);
+        printf("\n");
+
+        switch (selection)
+        {
+        case 1:
+            createBuses();
+            break;
+        case 2:
+            printBuses();
+            break;
+
+        case 3:
+            scheduleBuses();
+            break;
+        case 4:
+            alignupBuses();
+            break;
+
+        case 5:
+            releaseBuses();
+            break;
+
+        case 6:
+            emergency();
+            break;
+
+        default:
+            printf("You are enter incorrect option number");
+        }
+
+        confirm_on_finish();
+    };
+
+    return EXIT_SUCCESS;
+}
+
+int menu()
+{
+    fflush(stdout);
+
+    clrscr();
+
+    printf("\nQuestion 3 ");
+    printf("\n=========================================");
+    printf("\n");
+    printf("\n1. Create Buses");
+    printf("\n2. Print Buses");
+    printf("\n3. Schedule Buses");
+    printf("\n4. Align up Buses");
+    printf("\n5. Release Buses");
+    printf("\n6. Emergency Buses");
+
+    int chosen;
+    printf("\n\nEnter Your Selection : ");
+    scanf("%d", &chosen);
+    return chosen;
+}
+
+void createBuses()
+{
+
+    if (has_created == true)
+    {
+        printf("\nYou have created already...");
+        return;
+    }
+
+    printf("\n\nStart Create Buses...");
+
+    for (int i = 0; i < DEPOT_SIZE; i++)
+    {
+        top++;
+        Depot[i].BusID = i + 1;
+        Depot[i].RouteID = 1000 + (i + i);
+        printf("\n - Starting Create Bus %d", i + 1);
+    }
+
+    has_created = true;
+
+    printf("\nFinish Created Buses");
+}
+
+void printBuses()
+{
+    if (has_created == false)
+    {
+        printf("\nPlease Create Buses First!");
+        return;
+    }
+    print_depot(Depot);
+}
+
+void scheduleBuses()
+{
+    if (has_created == false)
+    {
+        printf("\nPlease Create Buses First!");
+        return;
+    }
+
+    printf("\nStart Scheduling Buses...\n\n");
+
+    size_t currentLen = sizeof(Depot) / sizeof(Depot[0]);
+
+    for (int i = 0; i < currentLen; i++)
+    {
+        printf("\n  - Start Random Schedule %d...", i);
+
+        Depot[i].schedule = get_random_time();
+    }
+
+    printf("\n\nEnd Scheduling Buses...");
+
+    has_scheduled = true;
+}
+
+void print_depot(struct Bus *depot)
+{
+
+    size_t currentLen = sizeof(Depot) / sizeof(*Depot);
+
+    for (int i = 0; i < top; i++)
+    {
+        printf("Bus ID: %d\n", depot[i].BusID);
+        printf("Route ID: %d\n", depot[i].RouteID);
+
+        char *scheduleForShow = "";
+        if (depot[i].schedule != 0)
+        {
+            scheduleForShow = ctime(&depot[i].schedule);
+        }
+
+        printf("Schdule Time : %s\n\n", scheduleForShow);
+    }
+}
+
+void alignupBuses()
+{
+    if (has_scheduled == false)
+    {
+        printf("\n\nYou are not scheduling buses yet ...");
+        return;
+    }
+    size_t currentLen = sizeof(Depot) / sizeof(Depot[0]);
+
+    qsort(Depot, sizeof(Depot) / sizeof(*Depot), sizeof(*Depot), quicksort_compare_func);
+
+    printf("\n\nFinish Align up Buses Schedule ... ");
+    has_aligned = true;
+}
+
+void releaseBuses()
+{
+    if (has_aligned == false)
+    {
+        printf("\n\nYou are not align buses schedule yet ...");
+        return;
+    }
+
+    int last_index = sizeof(Depot) / sizeof(*Depot) - 1;
+
+    remove_index_of_array(last_index);
+
+    printf("\n\nRelease Complete...\n\n");
+}
+
+void emergency()
+{
+    if (has_aligned == false)
+    {
+        printf("\n\nYou are not align buses schedule yet ...");
+        return;
+    }
+
+    remove_index_of_array(0);
+
+    printf("\n\nRelease Complete...\n\n");
+}
+
+void remove_index_of_array(int remove_index)
+{
+
+    int current_len = sizeof(Depot) / sizeof(*Depot);
+    memmove(Depot + remove_index, Depot + remove_index + 1, (sizeof(Depot) - remove_index - 1) * sizeof(*Depot));
+    top--;
+}
+
+time_t get_random_time()
+{
+    time_t currentTime;
+
+    time(&currentTime);
+
+    long currentTimeNumber = (long)localtime(&currentTime);
+
+    // Random in next 5 hours
+    long randomAddOnTime = rand() % (60 * 60 * 5);
+
+    long additionTime = currentTimeNumber + randomAddOnTime;
+
+    return additionTime;
+}
+
+void clrscr()
+{
+    system("clear");
+}
+
+void confirm_on_finish()
+{
+
+    printf("\n\nPress Enter to Back to Menu...");
+
+    getchar();
+    getchar();
+}
+
+bool isFull()
+{
+    return top == -1;
+}
+
+int quicksort_compare_func(const void *elem1, const void *elem2)
+{
+    struct Bus element1 = *((struct Bus *)elem1);
+    struct Bus element2 = *((struct Bus *)elem2);
+    if (element1.schedule > element2.schedule)
+        return -1;
+    if (element1.schedule < element2.schedule)
+        return 1;
+    return 0;
+}