Pythagorean Test in Java

Submitted by GeePee on Wednesday, May 6, 2015 - 23:09.

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:

import javax.swing.*; //required for GUI components
import java.awt.*; //required for use of the container
import java.awt.event.*; //contains the ActionListener interface to handle GUI events
 
public class abc
{
    public static void main(String[] args)
    {
        double a, b, bc, c; 
        String aStr, bStr, cStr, output; //declares our variables
        
        aStr = JOptionPane.showInputDialog("Enter a length of the hypotenuse: "); //prompts user
        a = Double.parseDouble(aStr); //sets a equal to the value input
        
        bStr = JOptionPane.showInputDialog("Enter a length of another side: "); //prompts user
        b = Double.parseDouble(bStr); //sets b equal to the value input
        
        cStr = JOptionPane.showInputDialog("Enter a length of the last side: "); //prompts user
        c = Double.parseDouble(cStr); //sets c equal to the value input
 
        bc = (b * b) + (c * c); //calculates the length of the two shorter sides squared
        
        if (bc == a * a) //conditional statement
            output = "This IS a right triangle."; //output to user
        
        else //if conditional is not satisfied
        
            output = "This is NOT a right triangle."; //output
            
        JOptionPane.showMessageDialog(null, output, "Calculation", JOptionPane.INFORMATION_MESSAGE); //displays output in GUI window
        
    }
}

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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