Structure as function argument in C

 A structure variable can be passed as an argument to a function.  It can be either passed by value or passed by reference.  The following example illustrates how to pass structure variable as a function argument.

Structure as function argument example:

  #include <stdio.h>
  #include <string.h>
  struct student {
        char name[100];
        int rollno;
        int age;
  };

  struct student update_static(struct student);
  void update_dynamic(struct student *);

  int main() {
        struct student s1;
        printf("update_static():\n");
        s1 = update_static(s1); // passing structure variable as argument
        printf("Name:%s\nRoll No.:%d\nAge:%d\n",
                s1.name, s1.rollno, s1.age);
        printf("update_dynamic():\n");
        update_dynamic(&s1);// passing address of structure variable as argument
        printf("Name:%s\nRoll No.:%d\nAge:%d\n",
                s1.name, s1.rollno, s1.age);
        return 0;
  }


  struct student update_static(struct student s) {
        strcpy(s.name, "Tom");
        s.rollno = 1010101;
        s.age = 1;
        return s;
  }

  void update_dynamic(struct student *s) {
        strcpy(s->name, "Jerry");
        s->rollno = 2010101;
        s->age = 2;
  }

  Output:

  jp@jp-VirtualBox:~/$ ./a.out
  update_static():
  Name:Tom
  Roll No.:1010101
  Age:1
  update_dynamic():
  Name:Jerry
  Roll No.:2010101
  Age:2