//执行环境是VC 6.0 //通过高斯消元法求解方程的解 //input: // 2 5 8 // 9 2 12 //output: // x1:1.073171 // x2:1.170732 //方程如下: //{2x + 5y = 8 //{9x + 2y = 12
#include <stdio.h> #include <stdlib.h>
void main( void ) { int n, i, j, k; double client, temp = 0.0; double **a;
printf("输入方式如下(系数以0表示无),最后一排是B的值:\n"); printf("4 5 2 3 2 5\n"); printf("4 6 2 1 0 2\n"); printf("4 5 2 1 3 2\n"); printf("1 2 1 2 3 2\n"); printf("0 2 5 1 1 3\n"); printf("请输入未知量的个数:"); scanf("%d", &n); printf("\n请输入系数矩阵和右端向量\n");
//分配内存空间 a = new double *[n]; for (i =0 ; i < n; i++) a[i]= new double[n + 1]; //输入数据 for (i = 0; i < n; i++) for (j = 0; j <= n; j++) scanf("%lf", (*(a + i) + j)); for(k = 0; k < n - 1; k++) for(i = k + 1; i < n; i++) { client = a[i][k]/a[k][k]; for(j = k + 1; j < n; j++) a[i][j] = a[i][j] - client * a[k][j]; a[i][n] = a[j - 1][n] - client * a[k][n]; } a[n - 1][n] = a[n - 1][n]/a[n - 1][n - 1]; for(i = n - 2; i >= 0; i--) { for (j = i + 1; j < n; j++) temp += a[i][j] * a[j][n]; a[i][n] = (a[i][n] - temp) / a[i][i]; }
for(i = 0; i < n; i++) printf("X%d = %lf\n", i + 1, a[i][n]); }

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