Thread: Simple Increment in a Loop error

It's probably something stupid, but I just can't see it as the same idea is working in the same code. Basically, it's a Rock, Paper, Scissors games - it ends when either the computer or user gets to 3, by declaring an int variable and incrementing it in the case of a win for either party. Loop then exits when get totalCompWin < 3 or totalUserWin < 3, I want the loop to exit as soon as it gets to 3 (so starts at 0, +1, +1 and next +1 exits loop. It exits fine once the user wins 3 times, but won't ever exit for the computer variable. Like I said, it's probably something stupid.

import java.util.Scanner;
 
 
public class rockPaperSci {
 
	public static void main(String args[])
	{
 
		// 0 is rock, 1 is scissors, 2 is paper
		Scanner input = new Scanner(System.in);
		int userInput = 0, compGo, totalUserWin = 0, totalCompWin = 0;
		double random;
 
 
 
			do{
				System.out.print("Enter 0 for Rock, 1 for Scissors, 2 for Paper: ");
				userInput = input.nextInt();
 
			//computer input
 
			random = Math.random() * 100;
			compGo = (int) random;
			compGo = compGo % 3;
 
			if (compGo == userInput)
				System.out.print("Draw. Go again.\n");
 
			else if (userInput == 0 && compGo == 1)
			{
				System.out.print("Rock beats Scissors! User wins!\n"); totalUserWin++;
			}
 
			else if (userInput == 1 && compGo == 2)
			{
				System.out.print("Scissors beat Paper! User wins!\n"); totalUserWin++;
			}
 
			else if (userInput == 2 && compGo == 0)
			{
				System.out.print("Paper beats Rock! User wins!\n"); totalUserWin++;
			}
 
			else if (userInput >= 3)
			{
				System.out.print("Please read. Enter between 0 and 2, not 3 or higher!!!");
			}
 
 
			//for all non user wins, Computer wins. No need to show results really - can be added later on. After displaying Computers Wins, TotalCompWin gets incremented.
 
			else 
			{
				System.out.print("Computer Wins! \n"); 
				totalCompWin++;
			}
 
 
 
		}while (totalCompWin < 3 || totalUserWin < 3);
 
//tried the below inside and outside while loop
 
			if (totalUserWin == 3)
				System.out.print("User Wins!!!!");
 
			else if (totalCompWin == 3)
				System.out.print("Rise of the Machines!!!! Computer whooped your candy ass!");
 
 
//end
 
 
 
 
	}
 
}

Yup, it definitely exits. Unless I'm being stupid, I thought that || meant OR so that the loop would continue while totalCompWin is less than 3 OR totalUserWin is less than 3. Once either hits 3, the loop should stop because one of them is 3. If I had && then the loop would continue until both hit 3, which is not what I want.

Here's a sample console input. I just entered 1. As you can see, Computer Wins! came up 3 times but didn't terminate. As soon as the user won, it terminated.

Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Draw. Go again.
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Draw. Go again.
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Draw. Go again.
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Scissors beat Paper! User wins!
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Scissors beat Paper! User wins!
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Computer Wins!
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Computer Wins!
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Computer Wins!
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Draw. Go again.
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Draw. Go again.
Enter 0 for Rock, 1 for Scissors, 2 for Paper: 1
Scissors beat Paper! User wins!
User Wins!!!!

Actually, you are right. It's only exiting when both are 3. I thought that it should exit when either of the variables hit 3, whichever one, it doesn't matter.

My idea was

Do

{

< code >

}
while (numberOfUserWins is less than 3 OR numberOfComputerWins is less than 3)

My understanding is that loop should terminate when either numberOfUserWins hits 3 or the other one does, not both. I would have thought (numberOFUserWins < 3 && numberOfCompWins < 3) would have given the current result

Will do. It'll wait until later when I don't have a 3 year old trying to hang off me!

Shall report back. This won't beat me!

Fixed, I think!

import java.util.Scanner;
 
 
public class rockPaperSci {
 
	/**
	 * @param args
	 */
	public static void main(String args[])
	{
 
		// 0 is rock, 1 is scissors, 2 is paper
		Scanner input = new Scanner(System.in);
		int userInput = 0, compGo, totalUserWin = 0;
		double random;
 
 
		do
		{
				System.out.print("Enter 0 for Rock, 1 for Scissors, 2 for Paper: ");
				userInput = input.nextInt();
 
			//computer input
 
			random = Math.random() * 100;
			compGo = (int) random;
			compGo = compGo % 3;
 
			//end computer random digit of either 0, 1 or 2.
 
			if (compGo == userInput)
				System.out.print("Draw. Go again.\n");
 
			else if (userInput == 0 && compGo == 1)
			{
				System.out.print("Rock beats Scissors! User wins!\n"); totalUserWin++;
			}
 
			else if (userInput == 1 && compGo == 2)
			{
				System.out.print("Scissors beat Paper! User wins!\n"); totalUserWin++;
			}
 
			else if (userInput == 2 && compGo == 0)
			{
				System.out.print("Paper beats Rock! User wins!\n"); totalUserWin++;
			}
 
			else if (userInput >= 3)
			{
				System.out.print("Please read. Enter between 0 and 2, not 3 or higher!!!");
			}
 
 
			//for all non user wins, Computer wins. No need to show results really - can be added later on. After displaying Computers Wins, TotalCompWin gets incremented.
 
 
 
			else 
			{
				System.out.print("Computer Wins! \n"); 
				totalUserWin--;
			}
 
 
 
		}
		while (totalUserWin <= 2 ^ totalUserWin <= -3);
 
//tried the below inside and outside while loop
 
			if (totalUserWin > totalCompWin)
				System.out.print("User Wins!!!!");
 
			else 
				System.out.print("Rise of the Machines!!!! Computer whooped your candy ass!");
 
 
//end
 
 
 
 
	}
 
}

Just used one variable for tracking score and an EXCLUSIVE OR (^) rather than an INCLUSIVE OR (||) in the loop. It kicks out if the user gets to 3 or the computer gets to -3!