Thread: Sending two strings into a constructor:

I did this using ArrayList<String> and my tests worked. Meaning I was able to read the strings in a different class through my constructor. However I want to use a string array because it will be easier to handle when I finish the program. I will send each players poker hand in and figure out who is the winner instead of putting it all onto a ArrayList and having to iterate through it. However whenever I did my check I am just printing null.

PokerFile class

void separateHands(String cards)
	{
		//ArrayList<String>playerOne = new ArrayList<String>();
		//ArrayList<String>playerTwo = new ArrayList<String>();
 
		String[] playerOne = new String[10];
		String[] playerTwo = new String[10];
 
		String[] parts = cards.split(" ");
 
			for(int i=0;i<5;i++)
			{	
				playerOne[i]=parts[i];
				//playerOne.add(parts[i]);
			}
 
			for(int j=5;j<10;j++)
			{
				playerTwo[j]=parts[j];
				//playerTwo.add(parts[j]);
			}
 
			new WinningHand(playerOne,playerTwo);
	  }

ignore the boolean methods I was just building the structure of the program. The print file is what is outputting this:

null
null
null
null
null
null

public class WinningHand extends PokerFile
{
	//ArrayList<String> p1 = new ArrayList<String>();
	//ArrayList<String> p2 = new ArrayList<String>();
	String[] p1 = new String[6];
	String[] p2 = new String[6];
 
	WinningHand(String[] p1,String[] p2)
	{
		this.p1=p1;
		this.p2=p2; 	
	}
	WinningHand()
	{
 
	}
 
	boolean pair(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean threeOfaKind(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean twoPair(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean flush(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean fullHouse(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean fourOfaKind(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean straightFlush(ArrayList<String> hand)
	{
		return true;
	}
 
	boolean royalFlush(ArrayList<String> hand)
	{
		return true;
	}
 
	void print()
	{
		for(String s: p2)
		{
			System.out.println(s);
		}
	}
 
	public static void main(String[] args)
	{
		PokerFile poker = new PokerFile();
		WinningHand hand = new WinningHand();
 
		poker.readFile();
		hand.print();
 
	}
 
}

String[] playerTwo = new String[10];
		String[] playerOne = new String[10];
 
 
		String[] parts = cards.split(" ");
 
			for(int i=0;i<5;i++)
			{	
				playerOne[i]=parts[i];
				//playerOne.add(parts[i]);
			}
 
			for(int j=5;j<10;j++)
			{
 
				playerTwo[j]=parts[j];
				//playerTwo.add(parts[j]);
			}
 
			new WinningHand(playerOne,playerTwo);

Here is the issue. Took me a second to see it. I cannot access the variables inside of the loop. Therefore I am not sending anything to the other class. So I thought I would be clever and try this but it didn't work.

for(int i=0;i<5;i++)
				playerOne[i]=parts[i];
				//playerOne.add(parts[i]);
 
			for(int j=5;j<10;j++)
				playerTwo[j]=parts[j];
				//playerTwo.add(parts[j]);
 
			new WinningHand(playerOne,playerTwo);

Norm's questions are the kind of things you should be asking yourself to understand how to troubleshoot and debug your code yourself, so please give them serious consideration - answer them to yourself, and you may find the answer to your problem.

To put a sharper point on Norm's excellent questions, pick this statement apart:

hand.print();

I cannot access the variables inside of the loop.

Why not?

Therefore I am not sending anything to the other class.

That doesn't make sense, or your reasoning isn't easy to follow.

So I thought I would be clever and try this but it didn't work

for(int i=0;i<5;i++)

Avoid hard coding the for() statement values whenever possible.

Thank you guys.... Yes I am just going to stay with the ArrayList<String>

--- Update ---

I cannot just walk away from this. It is bugging me. Here is what I did and I get no errors but no output other then the "Hello" I print in main just to make sure something is working

public class WinningHand extends PokerCalculator
{
	private int p1Size;
	private int p2Size;
	private String[] p1Hand = new String[p1Size];
	private String[] p2Hand = new String[p2Size];
 
	WinningHand()
	{
		//System.out.println(p1.size());
	}
	WinningHand(ArrayList<String> p1, ArrayList<String> p2)
	{
		String[] player1 = new String[p1.size()]; 	
		String[] player2 = new String[p2.size()];
 
		player1 = p1.toArray(player1);
		player2 = p2.toArray(player2);
 
		p1Size= p1.size();
		p2Size= p2.size();
 
		this.p1Hand = player1;
		this.p2Hand = player2;
	}

Well both....

                this.p1Hand = player1;
		this.p2Hand = player2;

I thought this would copy one string to the other string array. However whenever I check its size it is zero.

When I use a loop in the constructor I get the output.

for(String s :p1Hand)
		{
			System.out.println(s);
		}

Therefore my issue is copying the values I am getting into a global private variable so i can use it in the rest of the program to run my checks.

one constructor takes parameters where as the other does not. If I try to execute the program it will ask for two strings unless I make a default constructor.

Track the data down? The constructor is working but it will not set values outside of it for whatever reason.

What is "nothing"? null or empty String or ???

empty

p1Hand is private. How are you accessing it?

in the constructor and setting its values. Then calling in within the same class.

public class WinningHand extends PokerCalculator
{
	private int p1Size;
	private int p2Size;
	private String[] p1Hand = new String[p1Size];
	private String[] p2Hand = new String[p2Size];
 
	WinningHand()
	{
		System.out.println(p1Size);	
	}
 
	WinningHand(ArrayList<String> p1, ArrayList<String> p2)
	{
		String[] player1 = new String[p1.size()]; 	
		String[] player2 = new String[p2.size()];
 
		player1 = p1.toArray(player1);
		player2 = p2.toArray(player2);
 
		this.p1Size= p1.size();
		this.p2Size= p2.size();
 
		this.p1Hand = player1;
		this.p2Hand = player2;
	}

Where is this happening?

The constructor

Which statements are doing what needs to be done?

The constructor

Try debugging the code by adding some println statements that print out messages when the code at the important points executes

I did in the constructor but cannot access the in any other method.

Java For Complete Beginners - class constructor

has examples of the same way I am trying to set the private variables.

Both

void separateHands(String cards)
	{
		ArrayList<String>playerOne = new ArrayList<String>();
		ArrayList<String>playerTwo = new ArrayList<String>();
 
		String[] parts = cards.split(" ");
 
			for(int i=0;i<5;i++)
			{	
				playerOne.add(parts[i]);
			}
 
			for(int j=5;j<10;j++)
			{
				playerTwo.add(parts[j]);
			}
 
			new WinningHand(playerOne,playerTwo);
	  }

package pokerHandCalculator;
 
import java.util.ArrayList;
 
public class WinningHand extends PokerCalculator
{
	private int p1Size;
	private int p2Size;
	private String[] p1Hand = new String[p1Size];
	private String[] p2Hand = new String[p2Size];
 
	WinningHand()
	{
		System.out.println(p1Size);	
	}
 
	WinningHand(ArrayList<String> p1, ArrayList<String> p2)
	{
		String[] player1 = new String[p1.size()]; 	
		String[] player2 = new String[p2.size()];
 
		player1 = p1.toArray(player1);
		player2 = p2.toArray(player2);
 
		this.p1Size= p1.size();
		this.p2Size= p2.size();
 
		this.p1Hand = player1;
		this.p2Hand = player2;
	}
 
void print()
	{
		System.out.println("Printing Hand 1");
		for(String s :p1Hand)
		{
			System.out.println(s);
		}
 
		System.out.println("Printing Hand 2");
		for(String s :p2Hand)
		{
			System.out.println(s);
		}
 
		System.out.println(p1Hand.length);
	}
 
	public static void main(String[] args)
	{
		PokerCalculator poker = new PokerCalculator();
		WinningHand hand = new WinningHand();
 
		poker.readFile();
		hand.print();
 
	}
 
}

output:

Printing Hand 1
Printing Hand 2
0

Its quite obvious why you dont get your desired output in the example program you have posted.
This is how you construct your instance of WinningHand:

WinningHand hand = new WinningHand();

Here you use the constructor which has no parameters.

This is how the constructor is defined:

	WinningHand()
	{
		System.out.println(p1Size);	
	}

Notice how "p1Hand" and "p2Hand" are never assigned any values in this constructor.
So it is only natural that if you try to print this WinningHand you will get an empty output. Your variables contain empty string arrays of size 0.

Your second constructor could be used to initialize these variables to meaningful values, but that second constructor is never being used.

Yes I did try this already:

public static void main(String[] args)
	{
		ArrayList<String> p1 = new ArrayList<String>();
		ArrayList<String> p2 = new ArrayList<String>();
 
		PokerCalculator poker = new PokerCalculator();
		WinningHand hand = new WinningHand(p1,p2);
 
		poker.readFile();
		hand.print();
 
	}

I have used this method in C++ many times with no issue. However since it didn't made an empty default constructor. Which is why i said both are executing because I am getting output from both.