This question has been asked to me for many times by my algorithm teachers. I just wanted to write about it to help new algorithm students to find the answer to their homeworks :)
Let a and b be two integer variables. To swap the values of these variables, some arithmetic operations as follows must be applied.
a = a - b;
b = b + a;
a = b - a;
Lets continue with a numerical example where
a = 3 and b = 5
a = 3 - 5 = -2;
b = 5 + (-2) = 3;
a = 3 - (-2) = 5;
As a result of these operations, the values are swapped without using any additional temporary variable. Now you can write down the answer to your homework :)
