/*** [description] 求n阶矩阵的行列式* @Author fan_zhang* @DateTime -02-27T22:12:58*/#include <stdio.h>#include <stdlib.h>double det(double* , int );int main(int argc, char const* argv[]){int i, j, n ;double* a;printf("输入行列式的阶数:");scanf("%d", &n);a = (double*)malloc(sizeof(double) * n * n);if(a==NULL){printf("没有可用内存!\n");exit(0);}printf("输入%d个数;",n*n );for (i = 0; i < n; i++)for (j = 0; j < n; j++)scanf("%lf", a + i * n + j);printf("detA=%g\n", det(a, n));free(a);return 0;}double det(double* a, int N)//数组a[N][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) {//a[i][j]检查主对角线是否为0for (m = i + 1; m < N && a[m * N + j] == 0; m++)//a[m][j];if (m == N)//全为0则行列式为0return 0;elsefor (n = j; n < N; n++) {//交换两行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--) {//列变换成上三角行列式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;}
运行结果
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