Q. C program to swap two numbers without using temporary or any third variable.

Here you will find an algorithm and program in C programming language to swap 2 numbers without using any third or temporary variable.

Swapping two number : Swap two numbers means exchange the values of two variables with each other. Suppose we are given 2 numbers num1 = 10 and num2 = 20 and we have to swap these 2 numbers without using third variable. After swaping value of num1 = 20 and num2 = 10.

START
Step 1 ->  Take two integer num1 and num2.
Step 2 ->  Print number before swapping
Step 3 ->  num1 = num1 + num2;
Step 4 ->  num2 = num1 - num2;
Step 5 ->  num1 = num1 - num2;
Step 6 ->  Print numbers after swapping
STOP

C Program to Swap Two Numbers Without Using Temporary Variable

#include <stdio.h>
int main()
{
	int num1,num2;
	printf("Enter Two Numbers :\n");
	scanf("%d %d",&num1,&num2);
	printf("Number before swapping is %d and %d \n",num1,num2);
	num1=num1+num2;
	num2=num1-num2;
	num1=num1-num2;
	printf("Number after swapping is %d and %d \n",num1,num2);
	return 0;
}

Output

Enter Two Numbers :
10 15
Number before swapping is 10 and 15
Number after swapping is 15 and 10