A little program I wrote to do my precal homework problems for me.

Lines.java

import java.lang.Math;
import java.util.*;

public class Lines {

    public CoordSet first;
    public CoordSet second;

    public static class CoordSet {

        public double x, y, h, k;

        public CoordSet(double x, double y, double h, double k) {
            this.x = x;
            this.y = y;
            this.h = h;
            this.k = k;
        }

        public CoordSet(String x, String y, String h, String k) {
            this.x = Double.valueOf(x);
            this.y = Double.valueOf(y);
            this.h = Double.valueOf(h);
            this.k = Double.valueOf(k);
        }

        public String toString() {
            return String.format("(%f, %f), (%f, %f)", this.x, this.y, this.h, this.k);
        }

        public double getSlope() {
            return ((h - x) / (k - y));
        }

        public double getReciprocalSlope() {
            return (-1.0D / this.getSlope());
        }
    }

    public Lines(CoordSet first, CoordSet second) {
       this.first = first;
       this.second = second;
    }

    public static void main(String[] args) {
        String s1 = args[0].split("\\|")[0];
        String s2 = args[0].split("\\|")[1];
        String[] a1 = s1.split("\\,");
        String[] a2 = s2.split("\\,");
        Lines lineSet = new Lines(new CoordSet(a1[0], a1[1], a1[2], a1[3]), new CoordSet(a2[0], a2[1], a2[2], a2[3]));
        System.out.println("Line 1: " + lineSet.first.toString());
        System.out.println(" => Slope: " + lineSet.first.getSlope() + ", " + lineSet.first.getReciprocalSlope());
        System.out.println("Line 2: " + lineSet.second.toString());
        System.out.println(" => Slope: " + lineSet.second.getSlope() + ", " + lineSet.second.getReciprocalSlope());
        // check for parallelness
        if (lineSet.first.getSlope() == lineSet.second.getSlope()) {
            System.out.println("Lines 1 and 2 are parallel.");
        } else {
            System.out.println("Lines 1 and 2 are not parallel.");
        }
        // check for perpendicularness
        if (lineSet.first.getSlope() == lineSet.second.getReciprocalSlope() && lineSet.first.getReciprocalSlope() == lineSet.second.getSlope()) {
            System.out.println("Lines 1 and 2 are perpendicular.");
        } else {
            System.out.println("Lines 1 and 2 are not perpendicular.");
        }
    }
}