二维数组实验题：按如下公式递归计算矩阵行列式的值：
提示信息：“Please enter matrix size n(1<=n<20):” “Please input matrix line
by line:\n” “matrix a:\n”
**输出格式要求：“Submatrix:\n” “DValue of the Submatrix is %6.1f\n” “%6.1f\t” “result = %f\n”
程序运行结果如下：
Please enter matrix size n(1<=n<20):3
Please input matrix line by line:
1 2 3
4 5 7
8 9 11
matrix a:
1.0 2.0 3.0
4.0 5.0 7.0
8.0 9.0 11.0
(注意:此处有一个空行)
Submatrix:
5.0 7.0
9.0 11.0
DValue of the Submatrix is -8.0
Submatrix:
4.0 7.0
8.0 11.0
DValue of the Submatrix is -12.0
Submatrix:
4.0 5.0
8.0 9.0
DValue of the Submatrix is -4.0
result = 4.000000
下面是代码：
#include <math.h> #include <stdio.h> #define CONST 1e-6 #define SIZE 20 void InputMatrix (double a[][SIZE], int n); double DeterminantValue(double a[][SIZE], int n); void SubMatrix(double a[][SIZE], double b[][SIZE], int n, int row, int col); void PrintMatrix(double a[][SIZE], int n); int main(void) { double a[SIZE][SIZE]; int n; double result; printf("Please enter matrix size n(1<=n<%d):", SIZE); scanf("%d", &n); printf("Please input matrix line by line:\n"); InputMatrix(a, n); printf("matrix a:\n"); PrintMatrix(a, n); printf("\n"); result = DeterminantValue(a, n); printf("result = %f\n", result); return 0; } // 函数功能： 输入一个n×n矩阵的元素 void InputMatrix (double a[][SIZE], int n) { int i, j; for (i = 0; i < n; i++) { for (j = 0; j < n; j++) { scanf("%lf", &a[i][j]); } } } // 函数功能： 计算n×n矩阵的行列式的值 double DeterminantValue(double a[][SIZE], int n) { int i = 0, j = 0; double temp, result, b[SIZE][SIZE]; if (n == 1) { result = a[0][0]; } else if (n == 2) { result = a[0][0] * a[1][1] - a[0][1] * a[1][0]; } else { result = 0.0; for (j = 0; j < n; j++) { SubMatrix(a, b, n, i, j); printf("Submatrix:\n"); PrintMatrix(b, n - 1); temp = DeterminantValue(b, n - 1); result += pow(-1, i + j) * a[0][j] * temp; printf("DValue of the Submatrix is %6.1f\n", temp); } } return result; } // 函数功能： 计算n×n矩阵a中第row行col列元素的(n-1)×(n-1)子矩阵b void SubMatrix(double a[][SIZE], double b[][SIZE], int n, int row, int col) { int i, j, ii = 0, jj = 0; for (i = 0; i < n; i++) { jj = 0; for (j = 0; j < n; j++) { if (i != row && j != col) { b[ii][jj] = a[i][j]; jj++; } } if (i != row && j != col) { ii++; } } } // 函数功能： 输出一个n×n矩阵的元素 void PrintMatrix(double a[][SIZE], int n) { int i, j; for (i = 0; i < n; i++) { for (j = 0; j < n; j++) { printf("%6.1f\t", a[i][j]); } printf("\n"); } }
