1. 代码

let a = 3; 
let b = 4;
a = a ^ b;
b = a ^ b;
a = a ^ b;

2. 异或的性质

1. 不同为1,相同为0(可以看做是无进制位的加法)
2. 交换律: a ^ b = b ^ a;
3. 结合律: (a ^ b) ^ c = a ^ (b ^ a);
4. 0 ^ x = x;
5. x ^ x = 0;

3. 证明

下面证明1中的代码

1. a = 3 ^ 4;
2. b = (3 ^ 4) ^ 4 = 3 ^ 0 = 3;
3. a = (3 ^ 4) ^ 3 = 4 ^ 0 = 4;