Question

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How does XOR variable swapping work?
Swap the values of two variables without using third variable

How can I write a C code to swap 2 integer variables without using any extra variable?

Answer 1

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

Just use XOR operator for your purposes. Just for explanation

XOR (Exclusive Or) This operation is performed between two bits (a and
b). The result is 1 if either one of the two bits is 1, but not in the
case that both are. There for, if neither or both of them are equal to
1 the result is 0.

For example

a=5; //011
b=6; //100

a = a^b; //a=111
b = a^b; //b=011
a = a^b; //a=100