Swap two integers in 'C' programming Without using third variable

C program to swap two integers without using third variable

	#include <stdio.h>
	void main() {
	int a, b;
	printf("Enter two integer values for swapping : ");
	scanf("%d %d", &a, &b);
	printf("A = %d, B = %d\n", a, b);
	a = a + b;
	b = a - b;
	a = a - b;
	printf("After swapping :\n");
	printf("A = %d \t, B = %d\n", a, b);
	printf("===End===\n");
	}

view raw swap-NOnew-var.c hosted with ❤ by GitHub

Comments

[Frank Puffer]

While it does have some educational value to show that this is possible, this method has two issues:

• Both a = a + b and a = a - b can cause an overflow.

• I can't imagine many situations where saving a few bytes really makes up for the loss in readability.

[Günther Jena]

It also works with XOR (avoiding the overflow problem):

a = a ^ b
b = a ^ b
a = a ^ b

[Jason C. McDonald]

Agreed, this is definitely the way to do it.

[Joe Carnuccio]

reduced to one line:

a ^= b ^= a ^= b;