int getSum(int a, int b){
while(a & b)
{
unsigned int val_and = a & b;
//int val_and = a & b;
int val_xor = a ^ b;
val_and <<= 1;
a = val_and;
b = val_xor;
}
int result = a^b;
return result;
}
原文：https://www.cnblogs.com/ganxiang/p/13501829.html