大数相乘

# include <stdio.h># include <string.h>#define MAX 1005void chtoint(int num[], char ch[], int len);int main(void){char s1[MAX];char s2[MAX];int n;scanf("%d", &n);while (n--){int num1[MAX] = {0};int num2[MAX] = {0};int cmul[MAX] = {0};int csum[MAX] = {0};scanf("%s %s", s1, s2);int len1 = strlen(s1);int len2 = strlen(s2);chtoint(num1, s1, len1);chtoint(num2, s2, len2);int i, j, x;for (i = 0; i < len1; i++){int mul = 0;int c = 0;memset(cmul, 0, sizeof(cmul));for (j = 0; j <= len2; j++){mul = num1[i] * num2[j] + c;cmul[j] = mul % 10;//printf("cmul[%d] = %d\n", j, cmul[j]);c = mul / 10;//printf("c = %d\n", c);}int sum;int ci = 0;for (j = 0, x = i; x < MAX , j < MAX; x++){sum = csum[x] + cmul[j++] + ci;csum[x] = sum % 10;ci = sum / 10;}}for (i = MAX-1; i >= 0; i--){if (csum[i] != 0){break;}}for (; i >= 0; i--){printf("%d", csum[i]);}printf("\n");}return 0;}void chtoint(int num[], char ch[], int len){int i, j;for (i = len - 1, j = 0; i >= 0; i--){num[j++] = ch[i] - '0';}return ;}