How can I add a show all method and a delete method (that checks to make sure th

Question

How can I add a show all method and a delete method (that checks to make sure that the node trying to be delteted is inside thestructure) to this java data struture?

package perfecthashing;
public class PerfectHashedStructure
{   
Listing data[];
int size;
int minKey;
  
public PerfectHashedStructure(String minKey, String sMaxKey)
{
  
this.minKey = Integer.parseInt(minKey);
int maxKey = Integer.parseInt(sMaxKey);
size = maxKey - this.minKey + 1;
data = new Listing[size];
System.out.println(this.minKey + " " + size);
}
  
private int preprocess(String key)
{
int iKey = Integer.parseInt(key);
int pk = iKey - minKey;
return pk;
}
  
private int directHashing(int pk)
{
int ip = pk;
return ip;
}
  
public boolean insert(Listing aListing)
{
int pk = preprocess(aListing.getKey());
int ip = directHashing(pk);
Listing cloneListing = aListing.deepCopy();
if(data[ip] != null) // note with that key already in the structure
{
return false;
}
data[ip] = cloneListing;
return true;
}

public Listing fetch(String key)
{
int pk = preprocess(key);
int ip = directHashing(pk);

if(data[ip] == null) // node not in the structure
{
return null;
}
else
{
return data[ip].deepCopy();
}
}
}

*****************************************************************************
package perfecthashing;
import javax.swing.*;

public class PerfectHashing
{
public static void main(String[] args)
{ // Item number is the key field
   Listing l = new Listing("-9", "Textbook COM 101"); // ss number, name
   System.out.println(l);
  
   // declare the data structure object, ds
   String low = JOptionPane.showInputDialog("Enter min key");
   String high = JOptionPane.showInputDialog("Enter max key");
   PerfectHashedStructure ds = new PerfectHashedStructure(low, high);
  
Listing aListing = new Listing("-32", "first avenue 1234");
ds.insert(aListing);
System.out.println(ds.fetch("-32"));
System.out.println(ds.fetch("-2"));
System.out.println(ds.insert(aListing));
  
}
}
*****************************************************************************

package perfecthashing;

public class Listing
{
private String number; // key field
private String name;
  
public Listing(String num, String n )
{
number = num;
   name = n;
}
  
public String toString( )
{   
return("Item number is " + number +
" Name is " + name + " ");
}
  
public Listing deepCopy( )
{
Listing clone = new Listing(number, name);
return clone;
}
  
public String getKey()
{   
return number;
}
}// end of class Listing

Explanation / Answer

Below two methods can be added in class PerfectHashedStructure

public void showAll()
{
    for(int i=0; i<size; i++)
    {
        if(data[i]!=null)
        {
            System.out.print(data[i].toString());
        }
    }
  
}
public void deleteNode(Listing alisting)
{
    int pk = preprocess(alisting.getKey());
    int ip = directHashing(pk);
  
    if(data[ip]!=null)
    {
        data[ip]=null;
    }
    else
    {
        // No such node to delete
    }

}

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