C – Structure and Function

Just like any other variables that are passed in a function, structure can also be pas structs to functions. But before that you must go through the following topics in C.

• Structure In C
• Functions in C

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Passing structures to functions

While passing a structure we may pass the members of the structure or we can pass the structure variable itself. See the example below.

#include <stdio.h>

struct student 
{
   char name[50];
   int roll;
};

// function prototype
void display_function(struct student stud);

int main() 
{
   struct student s1;

   printf("Enter Student's name: ");
   scanf("%[^\n]%*c", s1.name);//reads until \n is entered

   printf("Enter the Student's Roll: ");
   scanf("%d", &s1.roll);

   display_function(s1); //struct variable is passed

   return 0;
}

void display_function(struct student stud) 
{
   printf("\n-------------DISPLAY---------\n");
   printf("Name of the Student: %s", stud.name);
   printf("\nRoll Number of the Student: %d", stud.roll);
}

Output:

Enter Student's name: Sherlock Holmes
Enter the Student's Roll: 101

-------------DISPLAY---------
Name of the Student: Sherlock Holmes
Roll Number of the Student: 101

The variable of the structure (s1) itself is passed into the display_function function as an argument.

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How to return a struct from a function

Go through the following example to see how a structure is returned from the function.

#include <stdio.h>

struct student
{
    char name[25];
    int roll;
};

// struct type function prototype
struct student stud_detail();

int main()
{
    struct student s;

    s1 = stud_detail();

    printf("\n---------DISPLAY--------\n");
    printf("Name of the Student: %s", s1.name);
    printf("\nRoll of the Student: %d", s1.roll);
    
    return 0;
}

struct student stud_detail() 
{
  struct student s;

  printf("Enter Student's name: ");
  scanf ("%[^\n]%*c", s.name);

  printf("Enter Roll Number: ");
  scanf("%d", &s.roll);
  
  return s;// returning struct variable
}	

Output:

Enter Student's name: Sherlock Holmes
Enter Roll Number: 101

---------DISPLAY--------
Name of the Student: Sherlock Holmes
Roll of the Student: 101

As you can see in the example, a separate structure variable (s) is declared inside the function (stud_detail()), and after entering all the information of the student, s is returned and displayed in the main function.

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