C语言计算行列式中的问题

Question

有没有友友帮忙看一下这个计算行列式的代码哪里有问题，真的写不出了

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <malloc.h>
double det1(int arr[10][10], int n)
{
    int sight = 1; double sum = 0; double s = 0; int p = -1; int arr2[10][10] = { 0 }; /*int* arr2 = (int*)malloc(sizeof(int) * n * n);*/
    if (n == 1)
        return arr[0][0];
    else if (n == 2)
        return arr[0][0] * arr[1][1] - arr[0][1] * arr[1][0];
    else
    {
        int i = 0; int a = 0, b = 0;
        for (i = 0; i < n; i++)
        {
            int k = 0; int l = 0;
            for (l = 1; l < n; l++)
            {
                for (k = 0; k < n; k++)
                {
                    if (k == l)
                        continue;
                    else
                        arr2[a][b] = arr[l][k]; b++;
                }
                a++;
            }
            s += sight * arr[0][i] * det1(arr2, n - 1); sight = -sight;
        }
        sum += s;
    }
    return sum;
}
int main()
{
    int i = 0; int k = 0; int n = 0;int arr[10][10] = { 0 };
    printf("请输入行列式阶数：");
    scanf("%d", &n);
    /*int* arr = (int*)malloc(sizeof(int) * n * n);
    if (arr == NULL)
    {
        printf("NULL");
        return 0;
    }*/
    if (n > 10)
        return 0;
    else
    {
        printf("请输入数据：");
        for (i = 0; i < n; i++)
            for (k = 0; k < n; k++)
            {
                scanf("%d", arr + i * n + k);
            }
        int p = 0;
    }
        double sum = det1(arr, n);
    
    /*free(arr); arr = NULL;*/
    printf("sum=%lf", sum);
    return 0;
}

Answer 1

修改如下，改动处见注释，供参考：

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <malloc.h>
double det1(int arr[10][10], int n)
{
    int sight = 1; double sum = 0; double s = 0; int p = -1; int arr2[10][10] = { 0 }; /*int* arr2 = (int*)malloc(sizeof(int) * n * n);*/
    if (n == 1)
        return  arr[0][0];
    else if (n == 2)
        return  arr[0][0] * arr[1][1] - arr[0][1] * arr[1][0];
    else
    {
        int i = 0; int a = 0, b = 0;
        for (i = 0; i < n; i++)
        {
            int k = 0; int l = 0;
            for (l = 1, a = 0; l < n; l++, a++) //for (l = 1; l < n; l++) 修改
            {
                for (k = 0,b = 0; k < n; k++) // for (k = 0; k < n; k++)  修改
                {
                    if (k == i) // if (k == l) 修改
                        continue;
                    else
                        arr2[a][b++] = arr[l][k]; //b++;  修改
                }
                //a++; 修改
            }
            s += sight * arr[0][i] * det1(arr2, n - 1); sight = -sight;
        }
        //sum += s;  修改
    }
    return s; //return sum; 修改
}
int main()
{
    int i = 0; int k = 0; int n = 0;int arr[10][10] = { 0 };
    printf("请输入行列式阶数：");
    scanf("%d", &n);
    /*int* arr = (int*)malloc(sizeof(int) * n * n);
    if (arr == NULL)
    {
        printf("NULL");
        return 0;
    }*/
    if (n > 10)
        return 0;
    else
    {
        printf("请输入数据：");
        for (i = 0; i < n; i++)
            for (k = 0; k < n; k++)
            {
                scanf("%d", &arr[i][k]);  // 修改
                //scanf("%d", arr + i * n + k);
            }
        //int p = 0;  修改
    }
    double sum = det1(arr, n);
    
    /*free(arr); arr = NULL;*/
    printf("sum=%lf", sum);
    return 0;
}