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Thread: Catch block problem. Please fix my problem.

  1. #1
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    Default Catch block problem. Please fix my problem.

    Im having a class GuessingGame.java that should compiles and runs. However, if the user enters something which is not a number (eg. "Dunno"), the program crashes. Add a catch block to the code so that instead of crashing, the program prints "That's not even a number!" and asks the user to pick another number as usual.

    This are my codes. I can't run this because I dont know how to use that "Catch-block" problem.

    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.io.IOException;
    import java.util.Random;

    public class GuessingGame
    {
    private int target;
    private BufferedReader in;

    public GuessingGame()
    {
    Random rand;

    rand = new Random();
    target = 1 + rand.nextInt(10);
    in = new BufferedReader (new InputStreamReader (System.in), 1);
    }

    private int guess()
    {
    String line;
    while (true)
    {
    try
    {
    System.out.print("Your guess: ");
    line = in.readLine();
    return Integer.parseInt(line);
    }
    catch (IOException e){
    System.out.println("That's not even a number!: " + e);
    } }

    }

    public void play()
    {
    int num;

    num = guess();
    while (num != target)
    {
    if (num < target)
    System.out.println("Higher");
    else if (num > target)
    System.out.println("Lower");
    num = guess();
    }
    System.out.println("You got it!");
    }

    public static void main(String args[])
    {
    HulaanMo game;
    game = new HulaanMo();
    System.out.println("Guess a number between 1 and 10");
    game.play();
    }
    }


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    Default Re: Catch block problem. Please fix my problem.

    Welcome to the forum! Please read this topic to learn how to post code correctly along with other useful info for newcomers.

  3. #3
    Member Ganeprog's Avatar
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    Default Re: Catch block problem. Please fix my problem.

    hi friend,

    you can use the while with in try and catch block like this,

    private int guess()
    {
    int line=0;                                      //chaned the datatype
    try
    {
    while (true)
    {
     
    System.out.print("Your guess: ");
    line = Integer.parseInt(in.readLine());  //Here i parse the string to int in a single statment
     
    }
     
    }
    catch (Exception e){                   //Here is given only Exception instead of IOException
    System.out.println("That's not even a number!: " + e);
    }
    return line;                                //Here i put return type
    }

    It may work.

    Thanks,
    Last edited by Ganeprog; February 2nd, 2014 at 11:38 PM. Reason: comments given

  4. #4
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    Default Re: Catch block problem. Please fix my problem.

    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.util.Random;
     
     
    public class Demo
    {
    	private int target;
    	private BufferedReader in;
     
    	public Demo()
    	{
    		Random rand;
     
    		rand = new Random();
    		target = 1 + rand.nextInt(10);
    		in = new BufferedReader (new InputStreamReader (System.in));
    	}
     
    	private int guess() throws Exception
    	{
    		int line;
    		while (true)
    		{
     
    				System.out.print("Your guess: ");
    				line = Integer.parseInt(in.readLine());
    				return (line);
    		}
     
    	}
     
    	public void play()
    	{
    		int num;
     
    		try
    		{
    		num = guess();
    		while (num != target)
    		{
    			if (num < target)
    				System.out.println("Higher");
    			else if (num > target)
    				System.out.println("Lower");
    			num = guess();
    		}
    		System.out.println("You got it!");
    		}
    		catch(Exception e)
    		{
    			System.out.println("That's not even a number! ");
    		}
     
    	}
     
    	public static void main(String args[])
    	{
    		Demo game;
    		game = new Demo();
    		System.out.println("Guess a number between 1 and 10");
    		game.play();
    	}
    }


    --- Update ---

    Please do study code.
    Last edited by Praful Chougale; February 3rd, 2014 at 12:48 AM. Reason: Msg

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