SOFTWARE

 /* swap A and B without a third var. */

/* Online C Compiler and Editor */

#include <stdio.h>

void swap( int a, int b)

{

printf("Before the swap A is : %d and B is %d \n", a, b);

// Store the sum of a + b in 'a''

a = a + b;

// Store the Difference of a - b in 'b'

b = a - b;

// Difference of sum and new 'b' is stored in 'a'

a = a - b;

printf("After the swap A is : %d and B is : %d \n", a, b);

}

int main()

{

int a = 10;

int b = 20;

swap(a, b);

return 0;

}

Result:

Before the swap A is : 10 and B is 20 

After the swap A is : 20 and B is : 10