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Thread: Question in numbering

  1. #1
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    Default Question in numbering

    public class Area {
    	public static void main(String[] args) {
    		double radius;
    		double area;
    		radius = 10;
    		area = radius * radius * 3.1415 ;
    		System.out.println("The area of circle is " + area + ".");
    	}
    }
    I am a newbie here. LOL
    I would like to ask why the result comes:

    "The area of circle is 314.15000000000003." ???
    Last edited by copeg; September 18th, 2010 at 11:06 AM. Reason: Please use the code tags


  2. #2
    Administrator copeg's Avatar
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    Default Re: Question in numbering

    What output would you expect?

  3. #3
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    Default Re: Question in numbering

    This is a normal thing. Your computer can only be so accurate. It is not a program problem, but rather that you computer has calculated it as best as possible. I don't really know how to explain it.

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  5. The Following User Says Thank You to Darryl.Burke For This Useful Post:

    cppcppcpp (September 20th, 2010)

  6. #5
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    Default Re: Question in numbering

    Quote Originally Posted by copeg View Post
    What output would you expect?
    I just expect it was

    "The area of circle is 314.15." before

  7. #6
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    Default Re: Question in numbering

    Now go through the page I linked and correct your expectations.

    db

  8. #7
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    Default Re: Question in numbering

    if you want to your answer to be displayed 314.15, you should put, "%2f, area" if im not mistaken its look like in the C programming it will just put 2 decimal place, i hope it can helps you.

  9. #8
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    Default Re: Question in numbering

    instead of this System.out.println("The area of circle is " + area + "."); use this System.out.printf("The area of cirlcis %3f" , area); so that the modulo will be read in the java compiler, with no problem

  10. #9
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    Default Re: Question in numbering

    @sanz:
    you're right..it's like C progmramming...

    @cppcppcppcpp

    change the System.out.println("The area of circle is " + area + ".");
    to:
    System.out.printf("The area of cirle is %.2f" , area);

  11. #10
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    Default Re: Question in numbering

    Should be getting 314.15 for the area... I got it..
    Now get more fun with it and require input from user.

    import java.util.*;

    public class Area {
    public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    double area;
    System.out.println("Please enter a radius");
    double radius = input.nextDouble();
    area = radius * radius * 3.1415 ;
    System.out.println("The area of circle is " + area + ".");
    }
    }