C Program to Swap two Variables Without a Third Variable

In many cases, we swap variables with help of a temp or third variable. Here is the C program to swap two variables without using a third variable.

Swapping two variables by no using the third variable is a common question in C interview questions.

C Program to Swap two Variables Without a Third Variable

#include<stdio.h>
int main(){
 int a=5,b=10;

//step one
 a=b+a;
 b=a-b;
 a=a-b;
 printf("a= %d b= %d",a,b);

//step two
 a=5;
 b=10;
 a=a+b-(b=a);
 printf("\na= %d b= %d",a,b);

//step three
 a=5;
 b=10;
 a=a^b;
 b=a^b;
 a=b^a;
 printf("\na= %d b= %d",a,b);
 
//step four
 a=5;
 b=10;
 a=b-~a-1;
 b=a+~b+1;
 a=a+~b+1;
 printf("\na= %d b= %d",a,b);
 
//step five
 a=5,
 b=10;
 a=b+a,b=a-b,a=a-b;
 printf("\na= %d b= %d",a,b);
 return 0;
}