n阶行列式计算

#include 
#include 

double det(double* a, int N)
{
    int i, j, m, n, s, t, k = 1;
    double f = 1.0, c, x;
    for (i = 0, j = 0; i < N && j < N; i++, j++) {
        if (a[i * N + j] == 0) {
            for (m = i + 1; m < N && a[m * N + j] == 0; m++)
            if (m == N)
                return 0;
            else
                for (n = j; n < N; n++) {
                    c = a[i * N + n];//a[i][n]
                    a[i * N + n] = a[m * N + n];//a[i][n]=a[m][n]
                    a[m * N + n] = c;//a[m][n]
                }
            k = -k;
        }
        for (s = N - 1; s > i; s--) {
            x = a[s * N + j];//a[s][j]
            for (t = j; t < N; t++)
                a[s * N + t] -= a[i * N + t] * (x / a[i * N + j]);
        }
    }
    for (i = 0; i < N; i++)//a[i][i]
        f *= a[i * N + i];
    return k * f;
}
int main()
{
    int i, j, n ;
    double* a;
    printf("请输入行列式的阶数:\n");
    scanf("%d", &n);
    a = (double*)malloc(sizeof(double) * n * n);
    printf("输入%d个数:\n",n*n );
    for (i = 0; i < n; i++)
        for (j = 0; j < n; j++)
            scanf("%lf", a + i * n + j);
    printf("result=%g\n", det(a, n));
    free(a);
    return 0;
}



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