cosmos

Your personal library of every algorithm and data structure code that you will ever encounter

Xor Swap

In computer programming, the XOR swap is an algorithm that uses the XOR bitwise operation to swap values of distinct variables having the same data type without using a temporary variable.

Proof of correctness

Let's say we have two distinct registers R1 and R2 as in the table below, with initial values A and B respectively.

Step	Operation	R1	R2
0	Initial	A	B
1	R1 := R1 ^ R2	A ^ B	B
2	R2 := R1 ^ R2	A ^ B	(A ^ B) ^ B => A
3	R1 := R1 ^ R2	(A ^ B) ^ A => B	A