fangcheng.java

可以求解线性方程组的解！只要在源文件中设置方程系数即可！

public class Fangcheng
{
	float a[][]={{31,-13,0,0,0,-10,0,0,0,-15},
		           {-13,35,-9,0,-11,0,0,0,0,27},
		           {0,-9,31,-10,0,0,0,0,0,-23},
		           {0,0,-10,79,-30,0,0,0,-9,0},
		           {0,0,0,-30,57,-7,0,-5,0,-20},
		           {0,0,0,0,-7,47,-30,0,0,12},
		           {0,0,0,0,0,-30,41,0,0,-7},
		           {0,0,0,0,-5,0,0,27,-2,7},
		           {0,0,0,-9,0,0,0,-2,29,10}};
	
		 
	void doShuZu()
	{ 
		  for(int k=0;k<8;k++)
		  {
			 for(int i=1+k;i<9;i++)
			  {
			    float m=a[i][k]/a[k][k];
			    for(int j=0;j<=9;j++)
			    {
			 	     a[i][j]=a[i][j]-m*a[k][j];
			    }
      
        }
		  }
		 System.out.println("方程的上三角矩阵为："); 
		for(int i=0;i<9;i++)
		 {
		 	for(int j=0;j<10;j++)
		   {
		   	System.out.print(a[i][j]);
		    System.out.print("  ");
		   }
		   System.out.println();
		  }
		 float x[]={0,0,0,0,0,0,0,0,0};
		 x[8]=a[8][9]/a[8][8];
		 for(int k=7;k>=0;k--)
		 {
		 float half=0;
		 	for(int i=k+1;i<9;i++)
		 	{
		 	  half=half+a[k][i]*x[i];
		  }
		  x[k]=(a[k][9]-half)/a[k][k];
		 
		}
		System.out.println("方程的根为");
	for(int i=0;i<9;i++)
		 {
		  System.out.print("x"+i+"="+x[i]);
		  System.out.print("         ");
		  if(i%2==0)System.out.println();
		 }
	}
	public static void main(String args[])
	{
		Fcheng dd=new Fcheng();
		dd.doShuZu();
		
	}
}