Question

a) A class Point3D is given. Re-write this class so that it meets the requirements for storage in our HashList<E> container Two points are considered equal if their x, y & z values are equal b) Test your class by creating a hash list of point3D instances and running relevant queries on your list (use MyHashList provided). The list should contain at least 10000 point instances. Part of your test should experiment with the number of lists in the table (the value of n passed to the constructor) to try to optimize the performance so that you don't get a large number of empty buffers and no buffer contains a large number of elements.

skeleton:

import java.util.*;

public class Point3D{

private int x,y,z;

Point3D(int a, int b, int c){

x = a; y = b; z = c;

}

public int x(){

return x;

}

public int y(){

return y;

}

public int z(){

return z;

}

public String toString(){

return "("+x+","+y+","+z+")";

}

}

Question1Test.java

import java.util.*;

public class Question1Test {

public static void main(String[] args){

MyHashList<Point3D> lst = new MyHashList<Point3D>(1000);

}

}

Answer 1

Hi,

The problem has been resolved. I have modified the "Point3D" class and "Question1Test" class for testing. You have not mentioned MyHashList class so I have not completed the Generic part of the code but I have tested this code on 10,000 recoreds. I'm getting radom value of x,y,z and creating objects and adding them to a arraylist because you have not given me this MyHashList class. After that the method "printEqualPoints" will print equals point.

When you want to read this code just change the number of time from 10000 to 100 and this maximum value of radom from 100 to 5 and uncomment the code. Then you will find the solution.

((int) (Math.random()*(100 - 1))) + 1 ->  ((int) (Math.random()*(5 - 1))) + 1

I'm attaching the running code screenshot for better understanding.

Screenshot:

Code:

-------------------------------

Point3D.class

------------

import java.util.*;
public class Point3D{
private int x,y,z;

Point3D(int a, int b, int c){
x = a; y = b; z = c;
}

public int getX(){
return x;
}

public int getY(){
return y;
}

public int getZ(){
return z;
}

public void setX(int a){
   this.x=a;
}
public void setY(int b){
   this.y=b;
}
public void setZ(int c){
   this.z=c;
}

public String toString(){
return "("+x+","+y+","+z+")";
}

}

------------

Question1Test.class

----------------

import java.util.*;
public class Question1Test {
   public static void main(String[] args){
   List<Point3D> list = new ArrayList<Point3D>(10000);

   Random random = new Random();

   for(int i=0;i<10000;i++){
       int a= ((int) (Math.random()*(100 - 1))) + 1;
       int b= ((int) (Math.random()*(100 - 1))) + 1;
       int c= ((int) (Math.random()*(100 - 1))) + 1;
       //System.out.println("a: "+a+" b: "+b+" c: "+c);

       list.add(new Point3D(a,b,c));
      
   }

   printEqualPoints(list);
  

   }

   static void printEqualPoints(List<Point3D> list){
       //System.out.println("here: "+list.size());
       for(int i=0;i<list.size();i++){
           Point3D obj1= list.get(i);

           for(int j=i;j<list.size();j++){
              
               Point3D obj2= list.get(j);

               //System.out.println(obj1.toString()+" -> "+obj2.toString());

               if(i!=j && obj1.getX()==obj2.getX() && obj1.getY()==obj2.getY() && obj1.getZ() == obj2.getZ()){

                   System.out.println("Point "+i+" and "+j+" are equal");
                   break;
               }

           }
       }
   }
}

----------------

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The problem has been resolved, I hope you will like the solution. If you have any question or query regarding this problem or other, please comment below and give the positive rating.

Thank You!! Happy Learning!! !!