c - 为什么随机值显示为输出以查找矩阵的行列式？

Question

我想通过使用 找到 M*M 矩阵的行列式递归在 C .
这是我在 Ubuntu 中尝试过的代码。

// Computing determinant of a MXM matrix

#include <stdio.h>

int determinant(int M, int A[10][10]) { //Function to calculate det(A)
    int i, j, k, m, n, p, q, pow = 1;
    int B[10][10];//assuming M does not cross 10
    if (M == 1)
        return A[0][0];
    else {
        det = 0;
        for (k = 0; k < M; k += 1) {
            m = 0;
            n = 0; //m,n are indices of subdeterminant of A
            for (i = 0; i < M; i += 1) {
                for (j = 0; j < M; j += 1) {
                    if (i != 0 && j != k) {
                        B[m][n] = A[i][j];  //finding submatrix
                        if (n < (k - 2))
                            n += 1;
                        else {
                            n = 0;
                            m += 1;
                        }
                    }
                }
            }
            det += pow * (A[0][k] * determinant(M - 1, B));
            pow = -1 * pow;
        }
        return det;
    }
}

int main() {
    int M, i, j;        // M is order of matrix A for which determinant has to be found
    printf("Enter the order of matrix: ");
    scanf("%d", &M);
    int A[10][10];
    printf("Enter matrix A: ");
    for (i = 0; i < M; i += 1) {
        for (j = 0; j < M; j += 1) {
            scanf("%d", &A[i][j]);  //Entering elements of matrix A
        }
    }
    printf("Given matrix A is: \n");
    for (i = 0; i < M; i += 1) {
        for (j = 0; j < M; j += 1) {
            printf("%d ", A[i][j]); 
        }
        printf("\n");
    }
    int det = determinant(M, A);
    printf("The determinant of given matrix is %d\n", det);
    return 0;
}

此代码适用于 2 阶矩阵。但对于更高阶的矩阵，输出是一些随机数。我无法确定这有什么错误。谁能解释为什么输出不符合预期以及如何纠正代码以获得预期输出？

Answer 1

提取子矩阵的内循环B来自 A似乎坏了。

这是一个更简单的版本:

        for (i = 1, m = 0; i < M; i++, m++) {
            for (j = 0, n = 0; j < k; j++, n++)
                B[m][n] = A[i][j];
            for (j = k + 1; j < M; j++, n++)
                B[m][n] = A[i][j];
        }