Add and updated functions

run

@@ -1,6 +1,9 @@
 #!/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
+
+gcc work1/single.c -o single
+./single

work1/single.c

@@ -1,34 +1,57 @@
 #include "stdio.h"
 #include "stdlib.h"
 
-struct person_tag {
+struct person_tag
+{
     char name[20];
     char id[10];
 };
 
-struct course_tag {
+struct course_tag
+{
     char course_name[20];
     int no_of_units;
     int marks[4];
     float avg;
 };
 
-struct student_tag {
+struct student_tag
+{
     struct person_tag student_info;
     struct course_tag course_info;
     struct student_tag *next;
-}
+};
 
-void display_students(void);
-void search_student(void);
-void find_maximum(void);
-void find_failed(void);
+// core functions
+void display_students();
+void search_student();
+void find_maximum();
+void find_failed();
 void update_file();
 void read_file();
 void quite();
 
-int main(void) {
-    printf("Welcome!");
+// util functions
+void display_menu();
 
-    printf("Goodbye!");
+int main(void)
+{
+    // varibales
+    int selected;
+
+    printf("Welcome!\n");
+
+    display_menu();
+
+    printf("\nGoodbye!");
+}
+
+void display_menu()
+{
+    printf("(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");
 }