Add two number using bit operation

I saw some articles telling about how to use bit-wise operation to achieve add operation.

Here the explanation for the function.


int add(int x, int y){
    int a,b;
    do{
        a = x & y;// a holds the carry (a承接进位)
        b = x ^ y;// b holds the sum without carry （b承接无进位的和）
        x = a<<1; // perform carry, x becomes carry （进位，并用x承接进位）
        y = b;
    }while（x) // until carry = 0 (直到无进位)
    return y;
}