Updated and can be read the student data from file

data/students.test.txt

@@ -0,0 +1,16 @@
+Jon
+1101825
+Computer
+4
+88
+98
+52
+95
+Jon
+1101825
+Computer
+4
+88
+98
+52
+95

work1/single.c

@@ -1,6 +1,10 @@
 #include "stdio.h"
 #include "stdlib.h"
 
+#define BUFFER_SIZE 128
+
+const char *FILE_STUDENT_DATA_PATH = "./data/students.test.txt";
+
 struct person_tag
 {
     char name[20];
@@ -20,7 +24,12 @@ 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;
 
 // core functions
 void display_students();
@@ -31,27 +40,189 @@ void update_file();
 void read_file();
 void quite();
 
+// Linked list functions
+void add_student(char *student_name, char *student_id, char *course_name, int no_of_units, int *marks);
+int count();
+
 // util functions
 void display_menu();
+void read_student_to_data();
+void print_welcome();
 
 int main(void)
 {
-    // varibales
+    // variable use for menu selected
     int selected;
 
-    printf("Welcome!\n");
+    print_welcome();
 
     display_menu();
 
+    display_students();
+
+    int c = count();
+
+    printf("Count: %d", c);
+
     printf("\nGoodbye!");
 }
 
+void print_welcome()
+{
+    printf("Welcome!\n");
+}
+
+void display_students()
+{
+    read_student_to_data();
+}
+
 void display_menu()
 {
-    printf("(1) Display students’ details\n");
+    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");
+    printf("(6) Quit program\n\n");
+}
+
+void add_student(char *student_name, char *student_id, char *course_name, int no_of_units, int *marks)
+{
+    STUDENT *temp, *iterator;
+    temp = (struct student_tag *)malloc(sizeof(struct student_tag));
+    PERSON info = {student_name, student_id};
+    COURSE course = {course_name, no_of_units, marks};
+    int sum = 0;
+    for (int i = 0; i < no_of_units; 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;
+    }
+}
+
+void update_file()
+{
+    FILE *file;
+    file = fopen(FILE_STUDENT_DATA_PATH, "a");
+}
+
+void read_student_to_data()
+{
+    // init head to null
+    head = NULL;
+
+    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[BUFFER_SIZE];
+    char student_id[BUFFER_SIZE];
+    char course_name[BUFFER_SIZE];
+    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';
+
+        printf("Student Name: %s\n", student_name);
+        printf("Student ID: %s\n", student_id);
+        printf("Course Name: %s\n", course_name);
+        printf("No of units: %s", no);
+
+        no_of_units = atoi(no);
+        for (int j = 0; j < no_of_units; j++)
+        {
+            char d[BUFFER_SIZE];
+
+            fgets(d, sizeof d, file);
+            sscanf(d, "%d", &marks[j]);
+        }
+
+        printf("Marks: [ ");
+        for (int x = 0; x < no_of_units; x++)
+        {
+            printf("%d ", marks[x]);
+        }
+        printf("]\n\n");
+
+        // add into linked list
+        add_student(student_name, student_id, course_name, no_of_units, marks);
+    }
+
+    fclose(file);
+}
+
+int count()
+{
+    int n = 1;
+    STUDENT *temp;
+    temp = head;
+    if (head == NULL)
+    {
+        return 0;
+    }
+
+    while (temp->next != NULL)
+    {
+        n++;
+        temp = temp->next;
+    }
+
+    return n;
 }