HDU1047 Integer Inquiry

#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <ctype.h>


using namespace std;

char num[105];
int sum[1000];

void add(char a[])
{
    int z=0;
    for(int i=strlen(a)-1;i>=0;i--)
    {
        sum[z]+=a[i]-‘0‘;
        sum[z+1]+=sum[z]/10;
        sum[z]%=10;
        z++;
    }
}
int main()
{
    int t,i;
    scanf("%d",&t);
    while(t--)
    {
        memset(num,‘ ‘,sizeof(num));
        memset(sum,0,sizeof(sum));

        while(scanf("%s",num)&&strcmp(num,"0"))
            add(num);

        for(i=999;i>=0;i--)
            if(sum[i])
                break;
        if(i<0)
            printf("0");
        for(;i>=0;i--)
            printf("%d",sum[i]);
            printf("\n");
        if(t!=0)
            printf("\n");

    }
    return 0;
}