大整数减法c语言代码

当处理大整数减法时，我们需要考虑两个大整数的长度以及借位的情况。以下是一个简单的C语言代码示例，用于实现大整数减法：

#include <stdio.h>
#include <string.h>

#define MAX_LEN 100

void reverse(char* str) {
    int len = strlen(str);
    for (int i = 0; i < len / 2; i++) {
        char temp = str[i];
        str[i] = str[len - i - 1];
        str[len - i - 1] = temp;
    }
}

void subtract(char* num1, char* num2, char* result) {
    int len1 = strlen(num1);
    int len2 = strlen(num2);

    // 反转两个大整数
    reverse(num1);
    reverse(num2);

    int borrow = 0;
    int i;
    for (i = 0; i < len2; i++) {
        int diff = (num1[i] - '0') - (num2[i] - '0') - borrow;

        if (diff < 0) {
            diff += 10;
            borrow = 1;
        } else {
            borrow = 0;
        }

        result[i] = diff + '0';
    }

    // 处理较长的大整数剩余的位数
    for (; i < len1; i++) {
        int diff = (num1[i] - '0') - borrow;

        if (diff < 0) {
            diff += 10;
            borrow = 1;
        } else {
            borrow = 0;
        }

        result[i] = diff + '0';
    }

    // 去除结果前面的0
    while (result[i - 1] == '0' && i > 1) {
        i--;
    }

    result[i] = '\0';

    // 反转结果
    reverse(result);
}

int main() {
    char num1[MAX_LEN];
    char num2[MAX_LEN];
    char result[MAX_LEN];

    printf("请输入第一个大整数：");
    scanf("%s", num1);

    printf("请输入第二个大整数：");
    scanf("%s", num2);

    subtract(num1, num2, result);

    printf("结果为：%s\n", result);

    return 0;
}

请注意，此代码仅适用于非负整数的减法运算。如果需要处理负数或更复杂的情况，请根据具体需求进行修改。