Weird issue with while loop ending/being skipped

I'm fairly new to Java (and programming in general). I've been getting everything done pretty easily so far but this issue is really frustrating me. I've been through things a thousand different ways and cannot figure out why it's doing this:

Here is my code:

Code :

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import java.util.Scanner;
 
public class Driver
{
    public static void main (String args [])
    {
      // Declare and instantiate a new coin object
		  Dice die1 = new Dice();
        Dice die2 = new Dice();
		  double account;
		  double wager;
		  int total;
        String userReady;
        boolean result;
 
      // Create keyboard object
        Scanner keyboard = new Scanner(System.in);
 
		// Initial game banner
	    	System.out.println("Welcome to the game of Simple Craps");
 
		// Create gambling account for user specified amount
			System.out.print("How much do you have to gamble? ");
			account = keyboard.nextDouble();
 
      // Determine if user is ready to play
			System.out.print("Are you ready to play (Y or N)? ");
			userReady = keyboard.nextLine();
 
      // Loop while the user wants to continue
        while (userReady.equalsIgnoreCase("Y"))
        {       
 
		   	// Display totalDollars
				System.out.println("You have $" + account + " remaining");
 
    	      // Determine how much the user wants to gamble
				System.out.print("How much would you like to bet? ");
     		   wager = keyboard.nextDouble();
 
				if (wager <= account && account > 0)
				{
        		 // Roll the dice
          	    die1.roll();
          		 die2.roll();
 
				// Retrieve and display results
					System.out.println("You rolled a " + die1.getDiceValue() + " and a " + 
		  						die2.getDiceValue() + " for a total of " + die1.add(die2));
 
						if (die1.add(die2) == 7 || die1.add(die2) == 11)
							{
								account += wager;
								System.out.println("You win $" + wager);
								System.out.println();
						 	}
						else if (die1.add(die2) == 2 || die1.add(die2) == 3 || die1.add(die2) == 12)
							{
								account -= wager;
								System.out.println("You lose $" + wager);
								System.out.println();
							}
						else 
						   System.out.println("Draw");
			    } //End if loop
 
 
 
        // Ask user if they want to try again
       		  System.out.println();
  	     	  	  System.out.print("Try again (Y or N)? ");
              userReady = keyboard.nextLine(); 
 
 
		   }//End while loop
 
 
 
     }//End main
 
}//End class

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And the problem is that the "Are you ready to play?" question does not seem to work

Here is sample output with the above code:

Quote:

---

----jGRASP exec: java Driver

Welcome to the game of Simple Craps
How much do you have to gamble? 123
Are you ready to play (Y or N)?
----jGRASP: operation complete.

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The very weird thing (at least to me), is that if I initialize account to 9.0 and remove the lines:

Code :

---

		// Create gambling account for user specified amount
			System.out.print("How much do you have to gamble? ");
			account = keyboard.nextDouble();

---

The program runs and outputs the following:

Quote:

---

Welcome to the game of Simple Craps
Are you ready to play (Y or N)? y
You have $9.0 remaining
How much would you like to bet? 1
You rolled a 1 and a 1 for a total of 2
You lose $1.0


Try again (Y or N)?
----jGRASP: operation complete.

---

Both are issues with the validation not working, but I'm at a loss as to why. Any ideas? Big thanks in advance, and let me know if you need any more information.

I changed the line

Quote:

---

// Ask user if they want to try again
System.out.println();
keyboard.nextLine();
System.out.print("Play again (Y or N): ");
userReady = keyboard.nextLine();

---

that takes place after the while loop, and now it works.

Somebody else suggested the extra keyboard.nextLine();, which worked. I've used that in the past but I can't remember how you know when/when not to use that. Any general rules to go by? Thanks

The reason is that the .nextDouble(), .nextInt(), etc. methods don't consume the new-line character. The user will type something like this:

"123\n" (\n comes from user hitting the return/enter key)

the .nextDouble() (and related) methods will consume 123, but \n is still left in the buffer. So, when nextLine() or next() is called, they return "" and consume the \n character.

in my opinion , i dont think so... because the compiler will execute and read sequentially each and every line of your code.. even the smallest space(i think so)...

so if the compiler encounters anything that IT CANT REACH... it will complain... because it cant reach it..

That's not true... It's possible to trick the compiler:

Code :

---

		boolean a = true;
		while (a)
		{
			System.out.println("Infinite loop!");
		}
		System.out.println("I tricked the compiler! This code is unreachable");

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