不用加减乘除做加法

#include <iostream>
#include <cstdio>
#include <cstring>
#include <stdlib.h>
using namespace std;
#define M 1001
int judge(int n,int m)
{
    if(m==0)
        return n;
    return judge(n^m,(n&m)<<1);
}

int main()
{
    int n,m;
    while(scanf("%d %d",&n,&m)!=EOF)
    {
        int ans=judge(n,m);
        printf("%d\n",ans);
    }
    return 0;
}