1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <malloc.h>
4
5 int GJ(int, double **);
6 double **TwoArrayAlloc(int, int);
7 void TwoArrayFree(double **);
8
9 void main()
10 {
11 int i, j, n;
12 double **a;
13 n = 4;
14 a = TwoArrayAlloc(n, n);
15
16 a[0][0] = 5; a[0][1] = 7; a[0][2] = 6; a[0][3] = 5;
17 a[1][0] = 7; a[1][1] = 10; a[1][2] = 8; a[1][3] = 7;
18 a[2][0] = 6; a[2][1] = 8; a[2][2] = 10; a[2][3] = 9;
19 a[3][0] = 5; a[3][1] = 7; a[3][2] = 9; a[3][3] = 10;
20 if (!GJ(n, a))
21 {
22 printf("矩阵求逆失败\n");
23 exit(1);
24 }
25 printf("该矩阵的逆为：\n");
26 for (i = 0; i<n; i++)
27 {
28 for (j = 0; j<n; j++)
29 printf("%.2f\t", a[i][j]);
30 printf("\n");
31 }
32 }
33
34 int GJ(int n, double **a)
35 {
36 int i, j, k;
37 double p, q, *h;
38 h = (double *)calloc(n, sizeof(double));
39 if (h == NULL)
40 {
41 printf("内存分配失败\n");
42 exit(1);
43 }
44 for (k = n; k >= 1; k--)
45 {
46 p = a[0][0];
47 if (p <= 0)
48 {
49 free(h);
50 return (0);
51 }
52 for (i = 2; i <= n; i++)
53 {
54 q = a[i - 1][0];
55 if (i>k)
56 h[i - 1] = q / p;
57 else
58 h[i - 1] = -q / p;
59 for (j = 2; j <= i; j++)
60 a[i - 2][j - 2] = a[i - 1][j - 1] + q*h[j - 1];
61 }
62 a[n - 1][n - 1] = 1 / p;
63 for (i = 2; i <= n; i++)
64 a[n - 1][i - 2] = h[i - 1];
65 }
66 free(h);
67 return(1);
68 }
69
70 double **TwoArrayAlloc(int r, int c)
71 {
72 double *x, **y;
73 int n;
74 x = (double *)calloc(r*c, sizeof(double));
75 y = (double **)calloc(r, sizeof(double*));
76 for (n = 0; n <= r - 1; ++n)
77 y[n] = &x[c*n];
78 return (y);
79 }
80
81 void TwoArrayFree(double **x)
82 {
83 free(x[0]);
84 free(x);
85 }
