UVA - 424 Integer Inquiry

#include<iostream>
#include<cstdio>
#include<string.h>
using namespace std;
int str[1000][1000];
char s[1000];
int ans[1000];
int main() {
int tot = 0;
int max = 0;
while(scanf("%s", s) != EOF) {
if (strcmp(s,"0") == 0) break;
int l = strlen(s);
if (l > max) max = l;
int j = 0;
for (int i = l-1; i >= 0; i--)
str[tot][j++] = s[i] - '0';
tot++;
}
for (int i = 0; i < max ; i++)
for (int j = 0; j < tot; j++){
ans[i] += str[j][i];
if (ans[i] > 9) {
ans[i+1]++;
ans[i] -=  10;
}
}
int i;
if (ans[max] == 0) i = max - 1;
else i = max;
for (; i >= 0; i--)
printf("%d", ans[i]);
printf("\n");

return 0;
}