Pass Entire Structure as Argument to Function in C

There are three ways by which the values of structure can be transferred from one function to another. They are as follows −

• Passing individual members as arguments to function.

• Passing entire structure as an argument to function.

• Passing the address of structure as an argument to function.

Now let’s see how to Pass an entire structure as an argument to function.

• Name of the structure variable is given as argument in function call.

• It is collected in another structure variable in function header.

• The disadvantage is that a copy of an entire structure is created again by wasting the memory.

Example

The following program shows how to pass an entire structure as an argument to function.

 Live Demo

#include<stdio.h>
struct date{
   int day;
   char month[10];
   int year;
};
int main(){
   struct date d;
   printf("enter the day,month and year:");
   scanf("%d%s%d",&d.day,d.month,&d.year);
   display(d);//passing entire structure as an argument to function
   return 0;
}
void display(struct date d){
   printf("day=%d
",d.day);
   printf("month=%s
",d.month);
   printf("year=%d
",d.year);
}

Output

When the above program is executed, it produces the following result −

enter the day, month and year:18 JAN 2021
day=18
month=JAN
year=2021

Example 2

Consider another example, wherein, a C program to demonstrate the passing of an entire structure as an argument to function is explained.

 Live Demo

#include<stdio.h>
//Declaring structure//
struct add{
   int var1;
   int var2;
}a;
//Declaring and returning Function//
void show(struct add a){
   //Declaring sum variable//
   int sum;
   //Arithmetic Operation//
   sum=a.var1+a.var2;
   //Printing O/p//
   printf("Added value is %d",sum);
}
void main(){
   //Declaring structure//
   struct add a;
   //Reading User I/p//
   printf("Enter variable 1 = ");
   scanf("%d",&a.var1);
   printf("Enter variable 2 = ");
   scanf("%d",&a.var2);
   //Calling function//
   show(a);
}

Output

When the above program is executed, it produces the following result −

Enter variable 1 = 20
Enter variable 2 = 50
Added value is 70

Example 3

An another C program to demonstrate the passing of an entire structure as an argument to function is given herewith which explains declaring structure, declaring and returning function etc.

 Live Demo

#include<stdio.h>
//Declaring structure//
struct student{
   int s1,s2,s3;
}s[5];
//Declaring and returning Function//
void addition(struct student s[]){
   //Declaring sum variable and For loop variable//
   int i,sum;
   //Arithmetic Operation//
   for(i=1;i<4;i++){
      sum=s[i].s1+s[i].s2+s[i].s3;
      printf("Student %d scored total of %d
",i,sum);
   }
}
void main(){
   //Declaring variable for For loop//
   int i;
   //Reading User I/p through For loop//
   for(i=1;i<4;i++){
      printf("Enter marks for student %d in subject 1 = ",i);
      scanf("%d",&s[i].s1);
      printf("Enter marks for student %d in subject 2 = ",i);
      scanf("%d",&s[i].s2);
      printf("Enter marks for student %d in subject 3 = ",i);
      scanf("%d",&s[i].s3);
   }
   //Calling function//
   addition(s);
}

Output

When the above program is executed, it produces the following result −

Enter marks for student 1 in subject 1 = 25
Enter marks for student 1 in subject 2 = 89
Enter marks for student 1 in subject 3 = 45
Enter marks for student 2 in subject 1 = 12
Enter marks for student 2 in subject 2 = 45
Enter marks for student 2 in subject 3 = 89
Enter marks for student 3 in subject 1 = 12
Enter marks for student 3 in subject 2 = 78
Enter marks for student 3 in subject 3 = 12
Student 1 scored total of 159
Student 2 scored total of 146
Student 3 scored total of 102