How do you swap two integer value without using temp variable?

Question

// Swapping value between two integer without using temp variable.
        int a = 5;
        int b = 7;

        Console.WriteLine("Before Swap.");
        Console.WriteLine("value of A is: {0}", a);
        Console.WriteLine("value of B is: {0}", b);

        Console.ReadLine();

O/P: Before Swap. value of A is: 5 value of A is: 7

After Swap. value of A is: 7 value of A is: 5

So how can you swap two integer value without using temp variable?

You are posting a brain teaser, but this is not really the right place for it. I even think I saw the solution before the edit... Perhaps you should post to puzzling.stackexchange.com ? — samy, Oct 09 '14 at 09:20

score 2 · Answer 1 · answered Oct 09 '14 at 09:18

2

Try:

 a = a + b;
 b = a - b;
 a = a - b;

answered Oct 09 '14 at 09:18

blfuentes

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score 2 · Answer 2 · answered Oct 09 '14 at 09:49

2

first method

a = a + b;
b = a - b;
a = a - b;

second method

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

answered Oct 09 '14 at 09:49

isxaker

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The reason to NEVER EVER DO #2: when `a == b` you lose the value altogether, `x^x==0` – AlanK Aug 12 '21 at 05:04

score 0 · Answer 3 · answered Oct 09 '14 at 09:18

0

a = a + b;
b = a - b;
a = a - b;

answered Oct 09 '14 at 09:18

Christian St.

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score 0 · Answer 4 · answered Oct 09 '14 at 09:35

0

You need to use the XOR operator:

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

This works because applying two times the XOR with the same value cancel the operation:

a ^ b ^ b => a

answered Oct 09 '14 at 09:35

SylvainL

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How do you swap two integer value without using temp variable?

4 Answers4

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