C语言位移实现两个数的加法

////  main.c//  Add////  Created by Macro on 13-3-15.//  Copyright (c) 2013年 Macro. All rights reserved.//#include <stdio.h>// 位运算实现两个数的加法int add(int a, int b) {    if (b == 0) {        return a;    }    return add(a ^ b, (a & b) << 1);}int main(int argc, const char * argv[]){    // insert code here...    printf("%d\n", add(3, 5));    printf("%d\n", add(9, -5));    return 0;}