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Thread: Is it the Math or is it my Methods?

  1. #1
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    Default Is it the Math or is it my Methods?

    Hi all. Ron here. It's been a few weeks. I hope everyone is well.

    What I have here is part of a program I'm working on. What I'm doing at this point is converting a Fahrenheit temperature to Celsius. Simple enough, but every time I run this thing, it keeps returning -0.0, no matter what. I can't figure out if it's the way I've keyed the formula or if I've done something wrong with the methods. Anyone care to chime in?

    import javax.swing.JOptionPane;
     
    public class Celsius
    {
    	public static void main(String[] args)
    	{	
    		String input;
    		double fahrenTemp;
     
    		fahrenTemp = getFahren();
    		convertTemp(fahrenTemp);
    		System.exit(0);
     
    	}
     
    	public static double getFahren()
    	{
    		String input = JOptionPane.showInputDialog("Please enter a Fahrenheit temperature from 0 to 10 "
    												+ "and I will convert it to Celsius for you.");
    		double fahrenTemp = Double.parseDouble(input);
    		return fahrenTemp;
    	}
    	public static void convertTemp(double fahrenTemp)
    	{
    		double toCelsius = (5 / 9) * (fahrenTemp - 32);
    		JOptionPane.showMessageDialog(null, "That would be " + toCelsius + " degrees Celsius.");
     
    	}
     
    }


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Is it the Math or is it my Methods?

    The code is using int arithmetic: 5/10 = 0
    vs 5.0/10 = 0.5

    Use some double values in divisions
    If you don't understand my answer, don't ignore it, ask a question.

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

    Praetorian (April 11th, 2013)

  4. #3
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    Default Re: Is it the Math or is it my Methods?

    Norm! That's it!! You rock! Thank you SO much.

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