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Thread: Help making an error message.

  1. #1
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    Default Help making an error message.

    I am new to programming and need help creating an error message for one of my programs. My question is how do I make java show an error if the user were to enter letters instead of a number and how can I make a loop to keep asking for the input and show the error as long as the input is not a number.

    The following is only part of my code and the only part I want to show an error message for incorrect input.

    	String YearString = JOptionPane.showInputDialog(null,
        			"Please enter a year, for example 1700:",
        			"Finding Easter",
        			JOptionPane.QUESTION_MESSAGE);
     
                    	int YEAR = Integer.parseInt(YearString);

    Thanks in advance to all who helped!


  2. #2
    Super Moderator copeg's Avatar
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    Default Re: Help making an error message.

    My question is how do I make java show an error if the user were to enter letters instead of a number and how can I make a loop to keep asking for the input and show the error as long as the input is not a number.
    A while loop would work in this scenario, looping until the year string validates. Rather than catching the exception, you could simply validate the string. For example in pseudo-code:
     
    String value = "";
    while ( isValid(value) ){
      value = //optionPane input
    }
     
    private boolean isValid(String s){
        //validate the string for digits.
    }

  3. The Following User Says Thank You to copeg For This Useful Post:

    Lost_Secret (February 1st, 2011)

  4. #3
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    Default Re: Help making an error message.

    Thank-you for the assistance!

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