Java编程

开发平台：

Java

Exercise5.java：源码内容

							class Exercise5{
  public static void main(String[]args){
    double temp;
    double x1,x2,x3,x4;
    int i,j,max,row,line;
    double[][] a={{1,1,0,3,4},{2,1,-1,1,1},{3,-1,-1,3,-3},{-1,2,3,-1,4}}; 
    for(i=0;i<4;i++){
      max=i; 
      for(j=i+1;j<4;j++){     
        if(a[i][i]<Math.abs(a[j][i])){
          max=j;
        }
      }
      if(a[max][i]==0){
      	System.out.println("矩阵A奇异"); 
      	break;
      }
      for(line=i;line<5;line++){       
        temp=a[max][line];
        a[max][line]=a[i][line];
        a[i][line]=temp;
      }
      for(row=i+1;row<4;row++){     
      	double key=a[row][i]/a[i][i];
        for(line=i;line<5;line++){
          a[row][line]=a[row][line]-key*a[i][line];
        }
      }
    }
    if(a[3][3]==0){
      System.out.println("矩阵A奇异"); 
    }else{
       x4=a[3][4]/a[3][3];      
       x3=(a[2][4]-x4*a[2][3])/a[2][2];
       x2=(a[1][4]-x4*a[1][3]-x3*a[1][2])/a[1][1];
       x1=(a[0][4]-x4*a[0][3]-x3*a[0][2]-x2*a[0][1])/a[0][0];
       System.out.println("x1="+x1); 
       System.out.println("x2= "+x2);
       System.out.println("x3="+x3);
       System.out.println("x4= "+x4);
     }
  }
}

						