Swap two integers without using a third variable for all range of integer values

Question

How to swap 2 integers without using a third variable such that it works for all ranges of integers. I know that generally we do the following logic.

        int a, b;

        a = 10;
        b = 30;
        a = a + b;
        b = a - b;
        a = a - b;

But this logic will fail if (a + b) gives the value more than the integer range. Is there any other logic?

you might want to refer to this post: http://stackoverflow.com/questions/26274628/how-do-you-swap-two-integer-value-without-using-temp-variable — Hatjhie, Oct 10 '14 at 02:03

score 2 · Accepted Answer · answered Oct 10 '14 at 02:04

2

I believe you're looking for the XOR swap:

if (a != b) {
    a ^= b;
    b ^= a;
    a ^= b;
}

answered Oct 10 '14 at 02:04

bmat

score 1 · Answer 2 · answered Oct 10 '14 at 02:03

1

You can use xor ...

x ^= y;
y ^= x;
x ^= y;

Source with a handy live demo.

answered Oct 10 '14 at 02:03

Ricky Smith

score 1 · Answer 3 · answered Oct 10 '14 at 02:06

1

int a=10;
int b=20;

a=a^b;
b=a^b;
a=a^b;
Console.WriteLine(a);
Console.WriteLine(b);

answered Oct 10 '14 at 02:06

Vikas Gupta

3 Answers3