十进制大数的加法运算

#include<iostream>
#include<stdio.h>
#include<string.h>
const int M=200;
using namespace std;
int main(){
    char buffer[M];
    int array[M][M],answer[M];
    int N,maxn,len,num_integers,carry,sum,digit,l;
    while(cin>>N){
        for(int k=1;k<=N;k++){
        maxn=-1;
        memset(array,0,sizeof(array));
        memset(answer,0,sizeof(answer));
        for(num_integers=0;num_integers<100;num_integers++ ){
            gets(buffer);
            if(strcmp(buffer,"0")==0) break;
            len=strlen(buffer);
            if(len>maxn)
                maxn=len;
            for(int j=len-1,m=0;j>=0;j--)
                array[num_integers][m++]=buffer[j]-‘0‘;
        }
        carry=0;
        for(int i=0;i<maxn+2;i++){
            sum=carry;
            for(int j=0;j<num_integers;j++){
                sum+=array[j][i];
                digit=sum%10;
                carry=sum/10;
                answer[i]=digit;
            }
        }
        for(l=maxn+2;l>=0;l--)
            if(answer[l]!=0)
                break;
        while(l>=0){
            cout<<answer[l--];
        }
        cout<<endl;
     }
    }
    return 0;
}