poj 1503 高精度加法

import java.math.BigInteger;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        BigInteger sum = BigInteger.valueOf(0);
        BigInteger a;
        a = cin.nextBigInteger();
        while (true) {
            sum = sum.add(a);
            if (a.compareTo(BigInteger.valueOf(0)) == 0)
                break;
            a = cin.nextBigInteger();
        }
        System.out.println(sum);
        cin.close();
    }
}

#include<stdio.h>
#include<string.h>

#define N 20000

int ans[N],f,max;

void hadd(char a[])
{
    f=0;
    int n=strlen(a);
    for(int i=n-1;i>=0;i--)
    {
        a[i]-='0';
        ans[f]+=a[i];
        ans[f+1]+=ans[f]/10;
        ans[f]%=10;
        f++;
        if(max<f) max=f;
    }
}

int main()
{
    memset(ans,0,sizeof(ans));
    while(1)
    {
        char s[N];
        scanf("%s",s);
        if(strlen(s)==1&&s[0]=='0') break;
        hadd(s);
    }
    int flag=0;
    for(int i=N-1;i>=0;i--)
    {
        if((!flag&&ans[i]!=0)||flag||(!flag&&i==0))
        {printf("%d",ans[i]);flag|=1;}
    }
    puts("");
    return 0;
}