Three methods of variable value Exchange

"title"Two variables A and b are known, and an algorithm is designed to exchange values of a and B. "Method 1" is the most traditional, broadest, and most famous method, adding a variable to the code as follows: int A, B; int C; c = A; A = b; b = C; "Method 2" Without adding a third variable, swap the values of A and B with the following code: int A, A; A = A+b; B = A-B; A = a-B;   Analysis, set the original value of a and B to execute code                      variable a        variable b int A, b                     a            b a=a+b                        a+b          b b=a-b                        a+b        A+b-b=a A=a-b                         a+b-(b) =a+b-a=b          A "but"This method is only suitable for the integral type and so on, and can not be too large, otherwise there will be overflow. "Method 3"Bit operations execute code variable a variable b a=a^b; A^b b
B=a^b; A^b A^b^b=a
A=a^b; A^b^a=b A
(XOR)