How to swap A and B without third variable?

Wrong solution:

a = 5, b = 7
a += b		// (12)
b = a - b	// (12 - 7 = 5)
a = a - b	// (12 - 5 = 7)

Note:
You can also face the Integer overflow issue:
https://rosettacode.org/wiki/Integer_overflow

Solution:

a = 5, b = 7
a = a ^ b	// (5 ^ 7 = 2)
b = a ^ b	// (2 ^ 7 = 5)
a = a ^ b	// (2 ^ 5 = 7)