/**
 * Equality check of floating-point numbers
 */
public class FPNumbersEqual {

    public static void main(String[] args) {

        float x = 1.0f - 0.1f - 0.1f - 0.1f - 0.1f - 0.1f;
        System.out.println("x = " + x);
        System.out.println("x == 0.5 = " + (x == 0.5f));

        double y = 1.0 - 0.1 - 0.1 - 0.1 - 0.1 - 0.1;
        System.out.println("y = " + y);
        System.out.println("y == 0.5 = " + (y == 0.5));

        // The textbook recommends using an epsilon of 1e-7 for comparing floats
        // and 1e-14 for comparing doubles
        double epsilon = 1e-7;
        System.out.println("x == 0.5 = " + (Math.abs(x - 0.5f) < epsilon));
        epsilon = 1e-14;
        System.out.println("y == 0.5 = " + (Math.abs(y - 0.5) < epsilon));
    }

}