Swapping - without a third variable in C.

#include <stdio.h>

void main() {
	int a, b;
	printf("Enter two integer values : ");
	scanf("%d %d", &a, &b);
	printf("Before swapping the values are a = %d, b = %d\n", a, b);
    a = a + b ;
    b  = a - b ;
    a = a - b ;
    
	printf("After swapping the values are a = %d, b = %d\n", a, b);
}