Pythagorean Test in Java

[kalmik]

The following is a basic Java GUI program allowing a user to input the lengths of a triangle's sides to find out if it is a right triangle or not.

Open notepad or any text editor, and paste in the following code:

1. import
   
   javax.swing.*
   
   ;
   
   //required for GUI components
   
2. import
   
   java.awt.*
   
   ;
   
   //required for use of the container
   
3. import
   
   java.awt.event.*
   
   ;
   
   //contains the ActionListener interface to handle GUI events
   
4. 
   
5. public
   
   class
   
   abc
   
6. {
   
7. public
   
   static
   
   void
   
   main(
   
   String
   
   [
   
   ]
   
   args)
   
8. {
   
9. double
   
   a, b, bc, c;
   
10. String
    
    aStr, bStr, cStr, output;
    
    //declares our variables
    
11. 
    
12. aStr =
    
    JOptionPane
    
    .showInputDialog
    
    (
    
    "Enter a length of the hypotenuse: "
    
    )
    
    ;
    
    //prompts user
    
13. a =
    
    Double
    
    .parseDouble
    
    (
    
    aStr)
    
    ;
    
    //sets a equal to the value input
    
14. 
    
15. bStr =
    
    JOptionPane
    
    .showInputDialog
    
    (
    
    "Enter a length of another side: "
    
    )
    
    ;
    
    //prompts user
    
16. b =
    
    Double
    
    .parseDouble
    
    (
    
    bStr)
    
    ;
    
    //sets b equal to the value input
    
17. 
    
18. cStr =
    
    JOptionPane
    
    .showInputDialog
    
    (
    
    "Enter a length of the last side: "
    
    )
    
    ;
    
    //prompts user
    
19. c =
    
    Double
    
    .parseDouble
    
    (
    
    cStr)
    
    ;
    
    //sets c equal to the value input
    
20. 
    
21. bc =
    
    (
    
    b *
    
    b)
    
    +
    
    (
    
    c *
    
    c)
    
    ;
    
    //calculates the length of the two shorter sides squared
    
22. 
    
23. if
    
    (
    
    bc ==
    
    a *
    
    a)
    
    //conditional statement
    
24. output =
    
    "This IS a right triangle."
    
    ;
    
    //output to user
    
25. 
    
26. else
    
    //if conditional is not satisfied
    
27. 
    
28. output =
    
    "This is NOT a right triangle."
    
    ;
    
    //output
    
29. 
    
30. JOptionPane
    
    .showMessageDialog
    
    (
    
    null
    
    , output, "Calculation"
    
    , JOptionPane
    
    .INFORMATION_MESSAGE
    
    )
    
    ;
    
    //displays output in GUI window
    
31. 
    
32. }
    
33. }
    

Save it as abc.java. This is important or it will not run correctly. (The filename must match the name of the class that is delcared at the top.) You may notice there are a lot of comments. This is to help anybody who reads it know what each small section of code does. Read through this and you will get a feel for how it works step-by-step.

Open a command line or terminal, and type "cd" (without quotes) followed by the path to where you saved the abc.java file. If you saved it in Documents, type "cd Documents" and hit enter. Now, type "javac abc.java" and hit enter, then "java abc" and the program will run.

You will be asked for three lengths, starting with the hypotenuse. The program basically works by squaring the hypotenuse, and the sum of the other two sides, and seeing if both squares are equal. If they are, it is a right triangle. The user is told at the end if the sides they input make up a right triangle or not.

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