Is there any other method to swap the values of 2 variables?

Question

I have the following program where i swap the values of 2 variables by using pointers. Can i swap them without using the variable "temp"?

Can i just use pointers to swap the values of 2 variables?.Please explain and comment.

#include <iostream.h>

main()

{

int i, *ptr_i;

int j, *ptr_j;

int temp;

i=7;

j=11;

cout<<"Value of i: "<<i<<"\n";

cout<<"Value of j: "<<j<<"\n\n";

ptr_i = &i;

ptr_j = &j;

temp = *ptr_i;

i = *ptr_j;

j = temp;

cout<<"Value of i: "<<i<<"\n";

cout<<"Value of j: "<<j<<endl;

system("pause");

}

Answer 1

This is how you swap two variables without an intermediate:

int a;

int b;

a^=b^=a^=b;

Similarly, you can swap values given just the pointers:

int* pa = &amp;a;

int* pb = &amp;b;

*pa^=*pb^=*pa^=*pb;

However, if pa and pb point to the same location, then *pa is zeroed, and *pb does not change in value - the swap fails.

This swapping procedure is called the triple-XOR swap and should be avoided.

Answer 2

int a,b;

a=a+b;

b=a-b;

a=a-b;