Add function struct and tags for person tag and course tag

Add header functions

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!");
+}

work1/single.c

@@ -0,0 +1,28 @@
+#include "stdio.h"
+#include "stdlib.h"
+
+struct person_tag {
+    char name[20];
+    char id[10];
+};
+
+struct course_tag {
+    char course_name[20];
+    int no_of_units;
+    int marks[4];
+    float avg;
+};
+
+void display_students(void);
+void search_student(void);
+void find_maximum(void);
+void find_failed(void);
+void update_file();
+void read_file();
+void quite();
+
+int main(void) {
+    printf("Welcome!");
+
+    printf("Goodbye!");
+}