Swap 2 variables without 3rd variable.

Hey this is quiet interesting in programming.
Typical SWAP functions usually use a 3rd variable to store the value of the one that you want to swap.

Ex:
Given:
X = 10
Y= 20
Result:
X = 20
Y= 10

X = X + Y -> X = 20 + 10 = 30
Y = X - Y -> Y = 30 - 10 = 20
X = X – A –> X = 30 – 20 = 10

You can also do it with the exclusive or bitwise operator

X=(X^=Y)^(Y^=X);