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  1. #1
    ertopp is offline Member
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    Default methods... SO confused!

    I have to write a methods program to calculate celsius and i am so lost. can anyone please help me? I keep getting "cannot find symbol" errors.



    public class FahrenheitToCelsius {

    public static void main(String[] args)
    {
    float fahrenheit, celsius;
    String input;
    celsius = calculateCelsius(fahrenheit);

    input = JOptionPane.showInputDialog("Enter the Fahrenheit temperature you wish to convert as a floating point number.");
    //Convert the input to float.
    fahrenheit = Float.parseFloat(input);
    }

    //Calculate Celsius
    public static float calculateCelsius(float f)
    {
    float celsius, fahrenheit;

    celsius = calculateCelsius(fahrenheit);
    return(5/9) * (fahrenheit-32);

  2. #2
    jammas615 is offline Senior Member
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    Default Re: methods... SO confused!

    If you look at your code, your giving celsius a value of calculateCelsius(fahrenheit). You need to look at the order you have things occuring and rearrange some stuff.

  3. #3
    ertopp is offline Member
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    Default Re: methods... SO confused!

    I'll be honest, I have no idea what you mean. Should that go under the calculatecelsius method? I am so new to Java and basically ready to pull my hair out.

  4. #4
    ertopp is offline Member
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    Default Re: methods... SO confused!

    I am getting so many errors it's not even funny. I don't have a clue how to change this.
    Can anyone tell me why my input boxes aren't even coming up?

  5. #5
    jammas615 is offline Senior Member
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    Default Re: methods... SO confused!

    You need to get your input BEFORE you call the calculateCelcius method.
    Here:
    Java Code:
    //get input
    input = JOptionPane.showInputDialog("Enter the Fahrenheit temperature you wish to convert as a floating point number.");
    //Convert the input to float.
    fahrenheit = Float.parseFloat(input);
    
    //call calculateCelcius
    celsius = calculateCelsius(fahrenheit);

  6. #6
    jammas615 is offline Senior Member
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    Default Re: methods... SO confused!

    I think you need to do some reading: The Really Big Index

  7. #7
    ertopp is offline Member
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    Default Re: methods... SO confused!

    I actually have read that. I have been all over the net, read my chapter 4 times, watched the book videos and emailed my teacher. I just don't seem to get it. And all of the errors I get aren't seeming to help.

  8. #8
    jammas615 is offline Senior Member
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    Default Re: methods... SO confused!

    The best thing to do is write what you want to do down:
    1. Ask user to input temperature in Fahrenheit.
    2. convert input to Celsius
    3. Show user temperature in Celsius.

    and now go through what you need to do this:
    1. A float variable for Fahrenheit
    2. A way to put user input into Fahrenheit variable
    3. A method that returns a float that converts Fahrenheit to Celsius
    4. Print the result
    3.

  9. #9
    Fubarable's Avatar
    Fubarable is offline Moderator
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    Default Re: methods... SO confused!

    Quote Originally Posted by ertopp View Post
    I actually have read that. I have been all over the net, read my chapter 4 times, watched the book videos and emailed my teacher. I just don't seem to get it. And all of the errors I get aren't seeming to help.
    Please stop whining and show the errors and maybe we can help you understand them. Sheesh.

  10. #10
    ertopp is offline Member
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    Default Re: methods... SO confused!

    I did make a separate post with the errors, thank you. and I am not whining. Just saying that I have read all of that material and it wasn't helpful. Thats why I came here. I was hoping someone could help me. I am not asking for the answer, I just want to understand better. I am not terrible with Java. Methods confuse me and I want to learn why things are the way they are.

  11. #11
    ertopp is offline Member
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    Default Re: methods... SO confused!

    I tweeked my program a bit and will copy what I have now. Does this not seem to match the algorithm you just posted? I am only asking because I feel like it makes sense to me, then I get a ton of errors on the public static float calculateCelsius line.

    This is what I have:

    Java Code:
    public class FahrenheitToCelsius {
    
      public static void main(String[] args){
      {
      	float fahrenheit, celsius;
      	String input;
    
      	input = JOptionPane.showInputDialog("Enter the Fahrenheit temperature you wish to convert as a floating point number.");
      	//Convert the input to float.
      	fahrenheit = Float.parseFloat(input);
    
      	celsius = calculateCelsius(fahrenheit);
    
      	celsius = JOptionPane.showMessageDialog(null, fahrenheit + " degrees fahrenheit =" + celsius + " degrees celsius");
      }
    
    
      	//Calculate Celsius
      	public static float calculateCelsius(float fahrenheit)
      	{
      		celsius = (5/9) * (fahrenheit - 32);
      		return celsius;
      	}
    
    
    
    
    
    		}
    
    }
    Last edited by Fubarable; 10-08-2011 at 04:36 AM. Reason: code tags added

  12. #12
    Fubarable's Avatar
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    Default Re: methods... SO confused!

    Quote Originally Posted by ertopp View Post
    I did make a separate post with the errors, thank you. and I am not whining. Just saying that I have read all of that material and it wasn't helpful. Thats why I came here. I was hoping someone could help me. I am not asking for the answer, I just want to understand better. I am not terrible with Java. Methods confuse me and I want to learn why things are the way they are.
    Your problem is that you need to study more as that's the only way to clear the confusion. Serious, it will help. Now for your current problem, please post your error messages here to keep the discussion from being fragmented. You should show which line is causing which error and show the actual error message itself.

    You will also want to change your style of programming. If you're finding your code is showing lots of errors, it means that you're adding code to bad code, something you should never do. Instead start with a simple program skeleton, be sure it compiles and then every time you add a new line or two of code, check that it compiles correctly before adding any more code. If it doesn't fix it first.

  13. #13
    ertopp is offline Member
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    Default Re: methods... SO confused!

    These are the errors:

    line 28: ';' expected
    public static float calculateCelsius(float fahrenheit)

    line 28: '.class' expected
    public static float calculateCelsius(float fahrenheit)

    line 28: illegal start of expression
    public static float calculateCelsius(float fahrenheit)

    line 28: ';' expected
    public static float calculateCelsius(float fahrenheit)

    line 28: illegal start of expression
    public static float calculateCelsius(float fahrenheit)

    ^

  14. #14
    ertopp is offline Member
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    Default Re: methods... SO confused!

    Ok I do study and am actually doing fairly well. I said methods confuse me. I take online courses so I basically teach myself. It's hard to teach yourself something you don't understand.

  15. #15
    Fubarable's Avatar
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    Default Re: methods... SO confused!

    Check your curly braces. You've got some where you shouldn't. Your code formatting is bad, and this is preventing you from seeing your errors. Use one consistent formatting style, myself, I recommend the one true brace style, but you should use whichever your teachers recommend since they are the ones who absolutely must be able to easily understand your code.

    So my assignment to you is this: go through your code, correct its formatting and check each and every brace. Get rid of extra unnecessary braces, and make sure that opening and closing braces match where they are supposed to match.

  16. #16
    ertopp is offline Member
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    Default Re: methods... SO confused!

    But I thought you were to have braces around the code in each method?

  17. #17
    Fubarable's Avatar
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    Default Re: methods... SO confused!

    Quote Originally Posted by ertopp View Post
    But I thought you were to have braces around the code in each method?
    Again, you have an extra set of braces. Find them.

  18. #18
    ertopp is offline Member
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    Default Re: methods... SO confused!

    Also, when I change braces around I get this error:
    line 40: reached end of file while parsing

    I use the layout provided by my book so I didn't know it was that bad.

  19. #19
    Fubarable's Avatar
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    Default Re: methods... SO confused!

    Look carefully here:

    Java Code:
      public static void main(String[] args){
      {
        float fahrenheit, celsius;
        String input;
    See anything extra?

  20. #20
    ertopp is offline Member
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    Default Re: methods... SO confused!

    yes, i do now. sorry. I have been staring at this program for hours.

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