PythagoreanTriples2.java

public class PythagoreanTriples2 {

/*
    "In a right angled triangle, the square on the hypotenuse is equal to
    the sum of the squares on the other two sides." - Pythagoras' Theorem.
*/

    /**
    *   Program:    PythagoreanTriples2.java
    *   Purpose:    Calculate series of right-angled triangles
    *   Creator     Chris Clarke
    *   Created:    09.05.2015
    *   Note:       Calculates all triples from a=3 to a=499.
    *   See also:   https://en.wikipedia.org/wiki/Pythagorean_triples
    */

    private static long a=3L, b=4L, c=5L;

    public static void main(String[] args) {

        System.out.println("Triangles with the following length sides are right-angled:");

        while (a<=500L) {
            calcSides(a);
            a+=2;
        } // end while

    } // end main()

    public static void calcSides(long a) {
    // given a, calculate b and c and display them all

    /*
        a is odd (Pythagoras, c. 540 BC):
        side a : side b = (a^2 - 1)/2: side c = (a^2 +1)/2

    */

        // calculate new values
        b = (a*a-1)/2;
        c = (a*a+1)/2;

        if (c<0) {  // exceeded maximum long number, become negative
            System.exit(0);
        } // end if

        if (!(a*a + b*b == c*c)) {
            return;
        } // if

        // print sides of right-angled triangle
        System.out.println(a+", "+b+", "+c);

    } // end calcSides()

} // end class PythagoreanTriples2