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What is pass by reference in C language?
Pass by reference in C programming language is the addresses which are sent as arguments.
Algorithm
An algorithm is given below to explain the working of pass by value in C language.
START Step 1: Declare a function with pointer variables that to be called. Step 2: Declare variables a,b. Step 3: Enter two variables a,b at runtime. Step 4: Calling function with pass by reference. jump to step 6 Step 5: Print the result values a,b. Step 6: Called function swap having address as arguments. i. Declare temp variable ii. Temp=*a iii. *a=*b iv. *b=temp STOP
Example program
Following is the C program to swap two numbers using pass by reference −
#include<stdio.h>
void main(){
void swap(int *,int *);
int a,b;
printf("enter 2 numbers");
scanf("%d%d",&a,&b);
printf("Before swapping a=%d b=%d",a,b);
swap(&a, &b);
printf("after swapping a=%d, b=%d",a,b);
}
void swap(int *a,int *b){
int t;
t=*a;
*a=*b; // *a = (*a + *b) – (*b = * a);
*b=t;
}Output
When the above program is executed, it produces the following result −
enter 2 numbers 10 20 Before swapping a=10 b=20 After swapping a=20 b=10
Let’s take another example to know more about pass by reference.
Example
Following is the C program to increment value by 5 for every call by using call by reference or pass by reference.
#include <stdio.h>
void inc(int *num){
//increment is done
//on the address where value of num is stored.
*num = *num+5;
// return(*num);
}
int main(){
int a=20,b=30,c=40;
// passing the address of variable a,b,c
inc(&a);
inc(&b);
inc(&c);
printf("Value of a is: %d
", a);
printf("Value of b is: %d
", b);
printf("Value of c is: %d
", c);
return 0;
}Output
When the above program is executed, it produces the following result −
Value of a is: 25 Value of b is: 35 Value of c is: 45
Updated on: 17-Mar-2021
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