不能使我的扫描仪工作

Question

import java.util.*;
import java.util.Scanner;
import java.io.*;


class Point
{
   /* Method to find the quadrant of both the points p and q*/

   public String quadrant(double xp, double yp, double xq, double yq){


        Scanner keyboard= new Scanner(System.in);
        System.out.print("Enter the first value for Xp: ");
        xp = keyboard.nextDouble();
        Scanner keyboard1 = new Scanner(System.in);
        System.out.print("Enter the first value for Yp: ");
        yp = keyboard.nextDouble();
        Scanner keyboard2= new Scanner(System.in);
        System.out.print("Enter the first value for Xq: ");
        xq = keyboard.nextDouble();
        Scanner keyboard3= new Scanner(System.in);
        System.out.print("Enter the first value for Yq: ");
        yq = keyboard.nextDouble();
       String p_quadrant=getQuadrant(xp,yp);
       String q_quadrant=getQuadrant(xq,yq);
       return "Point p is at "+p_quadrant+" and Point q is at "+q_quadrant;  
   }

   /* Method to get the quadrant of each passed point*/
   public String getQuadrant(double x, double y){
       if(x==0 && y==0){
           return "Origin";
       }
       else if(x==0){
           return "Y-axis";
       }
       else if(y==0){
           return "X-axis";
       }
       if (x >= 0) {
   return (y >= 0 ? "1st Quadrant":"4th Quadrant");
       } else {
return (y >= 0 ? "2nd Quadrant":"3rd Quadrant");
   }

   }
   /* Method to get the euclidean distance between p and q */
   public double euclidean(double xp, double yp, double xq, double yq){
   double euc_distance = 0.0;

   double x_square=Math.pow((xq-xp), 2);
   double y_square=Math.pow((yq-yp), 2);
   euc_distance= Math.sqrt(x_square+y_square);

   return euc_distance;
   }

   /* Method to calculate the slope */
   public double slope(double xp, double yp, double xq, double yq){

       double x_diff= xp-xq;
       double slope=0.0;

       /* Check applied to avoid a divide by zero error */
       if(x_diff == 0){
           System.out.println("Slope is undefined");
           System.exit(1);  
       }
       else{
           slope=(yp-yq)/x_diff;
       }
       return slope;  
   }


   public static void main (String[] args) throws java.lang.Exception
   {

   /* Creating an object of Points and calling each method individually and printing the value*/
   Points p = new Points();
   double euc=p.euclidean(2.3, 5.6,0.5,9);
   String quad=p.quadrant(0, -5.6,0,0);
   double slop=p.slope(0,0.5,0.6,9);
   System.out.print("Euclidean:"+euc+"\n Quadrant:"+quad+"\n Slope:"+slop);
   }
}

我不知道为什么我的扫描仪不工作。 我也没有错误。 我的工作是要求用户输入所有要点。 真的，我被卡住了，这应该在几个小时内完成，而且我正在使用带有新JDK的最新Eclipse。 编程和本站点XD的新手。

当我运行程序时，我得到了这个结果。 Euclidean：3.847076812334269象限：点p在Y轴上，点q在原点斜率上：14.166666666666668，我也没有任何错误

Answer 1

您需要更新提示，并摆脱不必要的扫描仪以解决此问题。 您的提示都要求输入“ first”值，并且从不使用keyboard1 -keyboard3。 该代码也可以正常工作：

Scanner keyboard= new Scanner(System.in);
    System.out.print("Enter the first value for Xp: ");
    xp = keyboard.nextDouble();
    System.out.print("Enter the first value for Yp: ");
    yp = keyboard.nextDouble();
    System.out.print("Enter the first value for Xq: ");
    xq = keyboard.nextDouble();
    System.out.print("Enter the first value for Yq: ");
    yq = keyboard.nextDouble();
    String p_quadrant=getQuadrant(xp,yp);
    String q_quadrant=getQuadrant(xq,yq);
    return "Point p is at "+p_quadrant+" and Point q is at "+q_quadrant;
}

另外，在您的main方法中，您不是创建Point（）对象，而是创建Points（）对象。 它确实给我一个错误。