coin flip assignment help

[jamie keene]

I need help writing the main method,

   import java.util.Random;

   public class Coin
   {
   //Instance Variable
      private boolean sideShowing; //true = heads, false = tails
      private Random randomNumberGenerator; 
   
   //No-arg Constructor method:
      public Coin()
      {
         sideShowing = false;
         randomNumberGenerator = new Random();
      }
   
   //Flip the coin
      public void flip()
      {
         sideShowing = randomNumberGenerator.nextBoolean();
      }
   
   //returns true
      public boolean equals(Coin coin2)
      {
         return sideShowing == coin2.sideShowing;
      }
   
   //returns string based on value of sideShowing
      public String toString()
      {
         if(sideShowing)
            return "Heads";
         return "Tails";
      }
   }

here is the outline for the main method

import java.util.Scanner;

public class Game
{
   public static void main(String args[])
   {
   // Create a Scanner object to read from the keyboard
      
   // Declare and instantiate two coin objects   
        
   // Declare a local variable to hold user input       
   
   // Prompt for and read the user choice: same or different
      
   // Flip the two coins
        
   // Display the results of the coin flip
   // Hint: use the Coin class toString() method
         
   // Display if the user wins or loses
   // Hint: use Coin class equals() method
}

[marc weber]

jamie keene wrote:I need help writing the main method...

here is the outline for the main method

import java.util.Scanner;

public class Game
{
   public static void main(String args[])
   {
   // Create a Scanner object to read from the keyboard
      
   //...

Okay, one step at a time. Create a Scanner object. How would you do this?

[jamie keene]

i've been working on it, and this is what i have so far, but i think i have it wrong

import java.util.Scanner;

public class Game
{
	public static void main(String args[])
	{
	Scanner keyboard = new Scanner(System.in);
	
	//Declare and instantiate two coin objects
		Coin coin1 = new Coin();
		Coin coin2 = new Coin();
		
	//declare local variable to hold user input
		String choice;
		
	//prompt for and read user choice
		System.out.println("Enter your choice (Same or Different): ");
		choice = keyboard.nextLine();
		
	//flip the two coins
		coin1.flip();
		coin2.flip();

	//Display results of coin flip
		if(coin1.equals(coin2))
		{
		 System.out.println("Computer flipped tails and tails"); //
		}
		else
		{
		System.out.println("Computer flipped heads and tails");
		}
	
	//Display if user wins or loses
		
	}
}

[Kurt Van Etten]

That's a good start! You've got a little logic error in your code to display the results of the coin tosses, though: if the coins are equal, are they necessarily both tails? However, since the instructor suggested just using the toString() method for this section of code, you might want to do something simpler than what you've got right now.

[prem pillai]

As Kurt said , you are almost there ... think a bit more ... you will get it right.

In the second last instruction , instructor is asking you to use toString() method to display the result of the coin flip. Just check that part.
In the last instruction , you have been asked to use equals()method and keep in mind that you have a local variable called "choice" with you holding the user input.

[jamie keene]

i'm completely lost though, its like i'm treading water, can anyone give me an example or anything?

[prem pillai]

Here is a hint for you.

      public String toString()   
      {   
         if(sideShowing)   
            return "Heads";   
         return "Tails";   
      }   

This is the toString() method in your Coin class. It returns a string "Heads" if the boolean variable "sideShowing" is TRUE. If sideShowing is FALSE , it returns a string "Tails". Now after flipping a coin (calling flip() method) , if you call this toString() method on the coin you have flipped , you will get a string value which represents the side of the coin. You just need to print that value.

Now try it...

[jamie keene]

i don't know how to use toString though

[jamie keene]

import java.util.Scanner;

public class Game
{
	public static void main(String args[])
	{
	Scanner keyboard = new Scanner(System.in);
	
	//Declare and instantiate two coin objects
		Coin coin1 = new Coin();
		Coin coin2 = new Coin();
		
	//declare local variable to hold user input
		String choice;
		
	//prompt for and read user choice
		System.out.println("Enter your choice (Same or Different): ");
		choice = keyboard.nextLine();
		
	//flip the two coins
		coin1.flip();
		coin2.flip();

	//Display results of coin flip
		System.out.println("Computer flipped " + coin1 + " and " + coin2);
		
	//Display resluts
		if(coin1.equals(coin2))
		{
		
		}
		else
		{
		
		}	
	}
}

so how do i make the coin1 == coin2 same and coin1 != coin2 different match the input from the user?

[Christophe Verré]

Passing a Coin variable to System.out.println will call the toString() method of that coin. (println method API)

[Christophe Verré]

so how do i make the coin1 == coin2 same and coin1 != coin2 different match the input from the user?

You're near the end. You compared if both coins are the same, or are different. Then what do you need ? To compare if the user input is "Same" or "Different". How do you do that ? There are many ways. One could be :
1. If coins are same and user input is "Same", then win
2. Else if coins are different and user input is "Different", then win
3. Else lose

[jamie keene]

if(coin1.equals(coin2))&& choice = same
		{
		 System.out.println("YOU WIN");
		} 

does that work? or will that be an error?
I don't know how to get the user input to read since it is a string, so by doing coice = same does that mean that if the user inputs same it will work?

[jamie keene]

import java.util.Scanner;

public class Game
{
	public static void main(String args[])
	{
	Scanner keyboard = new Scanner(System.in);
	
	//Declare and instantiate two coin objects
		Coin coin1 = new Coin();
		Coin coin2 = new Coin();
		
	//declare local variable to hold user input
		String choice;
		
	//prompt for and read user choice
		System.out.println("Enter your choice (Same or Different): ");
		choice = keyboard.nextLine();
		
	//flip the two coins
		coin1.flip();
		coin2.flip();

	//Display results of coin flip
		System.out.println("Computer flipped " + coin1 + " and " + coin2);
		
	//Display resluts
		if(coin1.equals(coin2))
		{
			if(choice.equals("Same"))
				System.out.println("YOU WIN");
				else
				System.out.println("YOU LOSE");
		}
		else
		{
			if(choice.equals("Different"))
				System.out.println("YOU WIN");
				else
				System.out.println("YOU LOSE");
		
		}	
	}
}

is there a way to get the computer play another round without having to rerun the program?

[Christophe Verré]

if(coin1.equals(coin2))&& choice = same

You compare Strings the same way you compared coins.

is there a way to get the computer play another round without having to rerun the program?

Make a loop and find a way to break out of the loop when the game is over (e.g. by asking the user if he wants to continue)

[jamie keene]

   import java.util.Scanner;

   public class Game
   {
      public static void main(String args[])
      {
         Scanner keyboard = new Scanner(System.in);
      
      //Declare and instantiate two coin objects
         Coin coin1 = new Coin();
         Coin coin2 = new Coin();
      
      //declare local variable to hold user input
         String choice;
         char repeat = 0;
         String input;
      
         do	
         {	
         
         //prompt for and read user choice
            System.out.println("Enter your choice (Same or Different): ");
            choice = keyboard.nextLine();
         
         //flip the two coins
            coin1.flip();
            coin2.flip();
         
         //Display results of coin flip
            System.out.println("Computer flipped " + coin1 + " and " + coin2);
         
         //Display resluts
            if(coin1.equals(coin2))
            {
               if(choice.equals("Same"))
                  System.out.println("YOU WIN");
               else if(choice.equals("same"))
                  System.out.println("YOU WIN");
               else
                  System.out.println("YOU LOSE");
            
            }
            else
            {
               if(choice.equals("Different"))
                  System.out.println("YOU WIN");
               else if(choice.equals("different"))
                  System.out.println("YOU WIN");
               else
                  System.out.println("YOU LOSE");
            
            //ask if user wants to play again
               System.out.println("Would you like to try again (yes or no): ");
               input = keyboard.next();
               repeat = input.charAt(0);
            }	
         }while (repeat == 'Y' || repeat == 'y');
      }
   }

but i get the error of an odd repeat.. and how can i count the wins/loses to total at the end?

this is what the error looks like

----jGRASP exec: java Game
Enter your choice (Same or Different):
same
Computer flipped Tails and Heads
YOU LOSE
Would you like to try again (yes or no):
yes
Enter your choice (Same or Different):
Computer flipped Tails and Tails
YOU LOSE
Enter your choice (Same or Different):

[Christophe Verré]

One thing first : there is a method called equalsIgnoreCase in the String class. Check it out and see if you can improve your code a bit.

[Christophe Verré]

At least three problems:
1. You're not asking the question everytime you lose.
2. You're not breaking out from the loop when you win
3. Why aren't you using readLine() like you did first ?

[sreeram koneru]

jamie keene wrote:

   import java.util.Scanner;

   public class Game
   {
      public static void main(String args[])
      {
         Scanner keyboard = new Scanner(System.in);
      
      //Declare and instantiate two coin objects
         Coin coin1 = new Coin();
         Coin coin2 = new Coin();
      
      //declare local variable to hold user input
         String choice;
         char repeat = 0;
         String input;
      
         do	
         {	
         
         //prompt for and read user choice
            System.out.println("Enter your choice (Same or Different): ");
            choice = keyboard.nextLine();
         
         //flip the two coins
            coin1.flip();
            coin2.flip();
         
         //Display results of coin flip
            System.out.println("Computer flipped " + coin1 + " and " + coin2);
         
         //Display resluts
            if(coin1.equals(coin2))
            {
               if(choice.equals("Same"))
                  System.out.println("YOU WIN");
               else if(choice.equals("same"))
                  System.out.println("YOU WIN");
               else
                  System.out.println("YOU LOSE");
            
            }
            else
            {
               if(choice.equals("Different"))
                  System.out.println("YOU WIN");
               else if(choice.equals("different"))
                  System.out.println("YOU WIN");
               else
                  System.out.println("YOU LOSE");
            
            //ask if user wants to play again
               System.out.println("Would you like to try again (yes or no): ");
               input = keyboard.next();
               repeat = input.charAt(0);
            }	
         }while (repeat == 'Y' || repeat == 'y');
      }
   }

but i get the error of an odd repeat.. and how can i count the wins/loses to total at the end?

this is what the error looks like

----jGRASP exec: java Game
Enter your choice (Same or Different):
same
Computer flipped Tails and Heads
YOU LOSE
Would you like to try again (yes or no):
yes
Enter your choice (Same or Different):
Computer flipped Tails and Tails
YOU LOSE
Enter your choice (Same or Different):

Just like you are asking for repeating the experiment again, you should probably check if the user entered "Same" or "Different" correctly or not every time and if they didn't entered the right answer for the choice question, you should probably ask them again to answer the question.