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Thread: another easy one, variable not initialized

  1. #1
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    Default another easy one, variable not initialized

    I have been staring at this for longer than I care to admit, I dont know why it says the variable hold may not have been initialized? Looks initialized to me. You guys are the best any insight you may have would be awesome.

    1 error found:
    File: E:\ClassPractice1\ClassPractice1\Question1_IfState ment.java [line: 32]
    Error: The local variable hold may not have been initialized


    import javax.swing.JOptionPane;
    import java.text.DecimalFormat;
     
    //This program practices JOptionPane and an IF statement.
     
    public class Question1_IfStatement
    {
      public static void main(String[] args)
      {
        String inputString;
        double first;
        double second;
        double hold;
     
        DecimalFormat formatter = new DecimalFormat("#0.00");
     
        inputString = JOptionPane.showInputDialog ("What is the first number: ");
        first = Double.parseDouble (inputString);
     
        inputString = JOptionPane.showInputDialog ("What is the second number: ");
        second = Double.parseDouble (inputString);
     
        if (first >= second)
        {
          hold = (first * second) + (first * 2);
        }
        if (second > first)
        {
          hold = (first + second) + (second * 5);
        }
     
     
        JOptionPane.showMessageDialog(null, formatter.format(hold));
     
      System.exit(0);
    }
    }


  2. #2
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    Default Re: another easy one, variable not initialized

    These are all local variables:
     public static void main(String[] args)
      {
        String inputString;
        double first;
        double second;
        double hold;
    None of them have been initialized.
    What variable is the one referenced in the error message? Has it been given a value before it is used?
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: another easy one, variable not initialized

    Please initialize your variable first.
    it means to specify its initial value.
    double hold = 0;
    your trying print/access you variable hold without any initial value on it.
    you thought that you have set a value on it because of your statement
    if (second > first)
        {
          hold = (first + second) + (second * 5);
        }

    as you can see, that is a conditional statement,
    what if the condition is false?
    then you might never write anything on your variable right?
    that why it gives you a compilation error.
    initialize it first
    double hold = 0;

  4. The Following User Says Thank You to dicdic For This Useful Post:

    meangreen2003 (February 21st, 2014)

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    Default Re: another easy one, variable not initialized

    Hi,

    "hold" is a local variable for main(String[]) method. Such variables are never initialized on its own. If you put these variables inside a constructure, then only it will be initialized to default variable.

    In your code, you are getting a compilation error "The local variable hold may not have been initialized" because compiler cannot process the statements (i.e. which initialize hold variable) inside if() statement while compiling. And when compiler checks for the statement "JOptionPane.showMessageDialog(null, formatter.format(hold));" it could not recognize the value for hold being initialized or assigned.

    If you put the statement "JOptionPane.showMessageDialog(null, formatter.format(hold));" inside if() block, your code will work fine. But, putting the same code in multiple if() block is not a good coding practise.

    So, there may be 2 approach:
    1. If you declaring local variable, then always initialize them while declaring.
    2. You can declare these variables globally and call a constructor to initialize them to desired value. Else default constructor will initialize those global variable to default values.

    Now, how to code the program is something which is completly upon the choice of programming taking into consideration best coding practices.

    Please let us know if you have any queries.
    Thanks and regards,
    Sambit Swain

  6. The Following User Says Thank You to Sambit For This Useful Post:

    meangreen2003 (February 21st, 2014)

  7. #5
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    Default Re: another easy one, variable not initialized

    You guys are awesome. Im guessing you are doing it for no pay as well which makes you twice as awesome. Setting a value of 0 for my variables worked great, Thanks again.

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