第八章第十二题（金融应用：计算税款）（Financial applications: calculating taxes）

第八章第十二题（金融应用：计算税款）（Financial applications: calculating taxes）

• **8.12（金融应用：计算税款）
  
  **8.12（Financial applications: calculating taxes）
  
  

• 参考代码：

  package chapter08;
  
  import java.util.Scanner;
  
  public class Code_12 {
      public static void main( String[] args ){
          double sx , sy , ex , ey ;
          line l1 = new line() ;
          line l2 = new line() ;
          Scanner in = new Scanner(System.in) ;
          System.out.print("Enter the endpoints of the first line segment:" ) ;
          sx = in.nextDouble() ;
          sy = in.nextDouble() ;
          ex = in.nextDouble() ;
          ey = in.nextDouble() ;
          l1.set(sx,sy,ex,ey);
          System.out.print("Enter the endpoints of the second line segment:" ) ;
          sx = in.nextDouble() ;
          sy = in.nextDouble() ;
          ex = in.nextDouble() ;
          ey = in.nextDouble() ;
          l2.set(sx,sy,ex,ey) ;
          l1.show_crosser_with(l2) ;
      }
  }
  
  class line{
      private double sx ;
      private double sy ;
      private double ex ;
      private double ey ;
      line(){
          this.sx = 0 ;
          this.sy = 0 ;
          this.ex = 0 ;
          this.ey = 0 ;
      }
      void set( double sx , double sy , double ex , double ey ){
          this.sx = sx ;
          this.sy = sy ;
          this.ex = ex ;
          this.ey = ey ;
      }
      void show_crosser_with( line line2 ){
          double k1 = (ey-sy)/(ex-sx) ;
          double k2 = (line2.ey-line2.sy)/(line2.ex-line2.sx) ;
          if( k1 == k2 ){
              System.out.println( "These two lines are parallel to each other !" ) ;
          }
          else{
              double csx , csy ;
              double b1 = sy - k1*sx ;
              double b2 = line2.sy - k2*line2.sx ;
              csx = (b2-b1)/(k1-k2) ;
              csy = k1*(b2-b1)/(k1-k2) + b1 ;
              System.out.println( "The intersecting point is: (" + csx + ", " + csy + ")" ) ;
          }
      }
  }
  
  

• 结果显示：

  Enter the endpoints of the first line segment:2 1 4 5
  Enter the endpoints of the second line segment:3 8 7 6
  The intersecting point is: (5.0, 7.0)
  
  Process finished with exit code 0