UVA 424 Integer Inquiry

#include <cstdio>#include <cstring>int main() {char str_1[120], sum[200] = {0};while (gets(str_1)) {char str[120] = {0};int len = strlen(str_1);if (len == 1 && str_1[0] == '0')break;for (int i = 0; i < len; i++)str[i] = str_1[len - 1 - i];for (int i = 0; i < len; i++) {int num = sum[i] + str[i] - '0';sum[i] = num % 10;if (num > 9)sum[i+1]++; }}int kong = 150;while (!sum[--kong]);for (int i = kong; i >= 0; i--) {printf("%d", sum[i]);}printf("\n");return 0;}