#include <stdio.h> #include <string.h> #define N 1000 void get(int *array) { char str[N] = {'\0'}; int len = 0; scanf("%s", str); len = strlen(str); for (int i = 0;i < len;i++) { array[i] = str[len - i - 1] - '0'; } array[len] = -1; } void big_multi(int *num1, int *num2, int *result) { int num1_index = 0; int num2_index = 0; int result_index = 0; int tmp_carry = 0; int tmp_result = 0; for (num1_index = 0; num1[num1_index] != -1; num1_index++) { for (num2_index = 0; num2[num2_index] != -1; num2_index++) { tmp_result = num1[num1_index] * num2[num2_index] + result[num1_index + num2_index] + tmp_carry; result[num1_index + num2_index] = tmp_result % 10; tmp_carry = tmp_result / 10; } result_index = num1_index + num2_index - 1; if (tmp_carry) { result[result_index++] = tmp_carry; } } result[result_index++] = -1; } void print(int *array) { int i = 0; int len = 0; for (i = 0; array[i] != -1; i++); len = i; printf("Product : "); for (i = len - 1; i >= 0; i--) { printf("%d", array[i]); } if (len == 0) { printf("0"); } printf("\n"); } int main(int argc, char **argv) { int num1[N] = {0}; int num2[N] = {0}; int result[2 * N] = {0}; //将数用数组来存，并从低位向高位存. get(num1); get(num2); //执行相乘操作 big_multi(num1, num2, result); print(result); return 0; }对该段代码进行完善

以下是对代码进行的一些完善和优化：

1. 在函数 `get()` 中，可以增加对输入字符串长度的判断，如果长度超过了数组的长度，则提示用户重新输入；
2. 在函数 `get()` 中，可以增加对负数和小数的判断，如果输入的字符串不符合要求，则提示用户重新输入；
3. 在函数 `big_multi()` 中，可以增加对数组越界的判断，如果结果数组长度超过了数组的长度，则提示用户重新输入；
4. 在函数 `print()` 中，可以将变量 `len` 的计算放到函数 `get()` 中，避免重复计算；
5. 在函数 `print()` 中，可以增加对结果数组中的所有数字都为零的情况的判断，如果结果数组中的所有数字都为零，则直接输出 "Product : 0"。

以下是完善后的代码：

#include <stdio.h> 
#include <string.h> 
#define N 1000 

void get(int *array) { 
    char str[N] = {'\0'}; 
    int len = 0; 
    do { 
        printf("Please enter a non-negative integer: "); 
        scanf("%s", str); 
        len = strlen(str); 
        if (len > N) { 
            printf("The length of the input integer exceeds the maximum length of the array!\n"); 
        } else { 
            int is_valid = 1; 
            for (int i = 0; i < len; i++) { 
                if (str[i] < '0' || str[i] > '9') { 
                    printf("The input integer contains non-numeric characters!\n"); 
                    is_valid = 0; 
                    break; 
                } 
            } 
            if (is_valid) { 
                for (int i = 0; i < len; i++) { 
                    array[i] = str[len - i - 1] - '0'; 
                } 
                array[len] = -1; 
                return; 
            } 
        } 
    } while (1); 
} 

void big_multi(int *num1, int *num2, int *result) { 
    int num1_index = 0; 
    int num2_index = 0; 
    int result_index = 0; 
    int tmp_carry = 0; 
    int tmp_result = 0; 
    for (num1_index = 0; num1[num1_index] != -1; num1_index++) { 
        for (num2_index = 0; num2[num2_index] != -1; num2_index++) { 
            if (num1_index + num2_index >= N) { 
                printf("The length of the result array exceeds the maximum length of the array!\n"); 
                return; 
            } 
            tmp_result = num1[num1_index] * num2[num2_index] + result[num1_index + num2_index] + tmp_carry; 
            result[num1_index + num2_index] = tmp_result % 10; 
            tmp_carry = tmp_result / 10; 
        } 
        result_index = num1_index + num2_index - 1; 
        if (tmp_carry) { 
            if (result_index >= N) { 
                printf("The length of the result array exceeds the maximum length of the array!\n"); 
                return; 
            } 
            result[result_index++] = tmp_carry; 
        } 
    } 
    result[result_index++] = -1; 
} 

void print(int *array) { 
    int i = 0; 
    int len = 0; 
    for (i = 0; array[i] != -1; i++); 
    len = i; 
    printf("Product : "); 
    if (len == 0 || (len == 1 && array[0] == 0)) { 
        printf("0"); 
    } else { 
        for (i = len - 1; i >= 0; i--) { 
            printf("%d", array[i]); 
        } 
    } 
    printf("\n"); 
} 

int main(int argc, char **argv) { 
    int num1[N] = {0}; 
    int num2[N] = {0}; 
    int result[2 * N] = {0}; //将数用数组来存，并从低位向高位存. 
    get(num1); 
    get(num2); 
    big_multi(num1, num2, result); 
    print(result); 
    return 0; 
}