Programming Or Algorithms Snippet

1. Swap value of 2 variable with out using any third variable.
Suppose

1.  a= 5
2.  b = 7
3.  a = a + b;  = 12;
4.  b =  a - b ;  =  5;
5.  a = a -b; = 7

 You can also swap two equal length array with out using any temporary third variable by looping and traversing the arrays.