no.11.c

中南大学C语言程序设计实习 1 实验一：C语言图形模式的设置 2 实习二：一元函数的图形绘制 3 实习三：二维图形的几何变换 4 实习四：非线性方程求根的二分法 5 实习五

#include "conio.h"
#include "stdio.h"

void gauss(float a[][4], float* b, float* x, int n)
{
    int k, i, j;
    float s;
    float l[10] = {0};    

    for (k = 0; k < n - 1; k++) {
        if ( a[k][k]  == 0 )
                continue;
        for (i = k + 1; i < n; i++) {
            l[i] = a[i][k] / a[k][k];
            for (j = k + 1; j <= n; j++) {
                a[i][j] = a[i][j] - l[i]*a[k][j];
            }
            b[i] = b[i] - l[i]*b[k];
        }    
    }
        
    for (i = n-1; i >= 0; i--) {
        s = 0;
        for (j = i + 1; j < n; j++)
                s = s + a[i][j] * x[j];
        x[i] = (a[i][n] - s) / a[i][i]; 
    }   
}

void print(float* x, int n)
{
    int i;
    for (i = 1; i <= n; i++) {
        printf("x[%d] = %4.2f \n", i, x[i-1]);
    }
}

int main()
{
    float a1[3][4] = {{1, 1, -1, 3}, {2, -1, 3, 0}, {-1, -2, 1, -5}};
    float b1[3] = {3, 0, 5};
    float x1[3] = {0};
    float a2[2][4] = {{1, -2, 3}, {2, 1, 4}};
    float b2[2] = {3, 4};
    float x2[2] = {0};
    gauss(a1, b1, x1, 3);
    print(x1, 3);
    printf("----------------------\n");
    gauss(a2, b2, x2, 2);
    print(x2, 2);
    getch();
    return 0;
}