Added Rectangle

Shapes/Line.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Drawing;
+
+namespace Shapes
+{
+       public class Line
+    {
+        public Point Point1 { get; private set; }
+        public Point Point2 { get; private set; }
+        public Color Color { get; set; }
+
+        /**
+         * Constructor based on x-y Locations
+         * @param x1                The x-location of first point -- must be a valid double.
+         * @param y1                The y-location of first point -- must be a valid double.
+         * @param x2                The x-location of second point -- must be a valid double.
+         * @param y2                The y-location of second point -- must be a valid double.
+         * @throws ShapeException   Exception throw if any parameter is invalid
+         */
+        public Line(double x1, double y1, double x2, double y2)
+        {
+            Color = Color.Black;
+            Point1 = new Point(x1, y1);
+            Point2 = new Point(x2, y2);
+        }
+
+        /**
+         *
+         * @param point1            The first point -- must not be null
+         * @param point2            The second point -- must not b e null
+         * @throws ShapeException   Exception throw if any parameter is invalid
+         */
+        public Line(Point point1, Point point2)
+        {
+            if (point1==null || point2==null)
+                throw new ShapeException("Invalid point");
+            Color = Color.Black;
+            Point1 = point1;
+            Point2 = point2;
+        }
+
+        /**
+         * Move a line
+         *
+         * @param deltaX            The delta x-location by which the line should be moved -- must be a valid double
+         * @param deltaY            The delta y-location by which the line should be moved -- must be a valid double
+         * @throws ShapeException   Exception throw if any parameter is invalid
+         */
+        public void Move(double deltaX, double deltaY)
+        {
+            Point1.Move(deltaX, deltaY);
+            Point2.Move(deltaX, deltaY);
+        }
+
+        /**
+         * @return  The length of the line
+         */
+        public double ComputeLength()
+        {
+            return Math.Sqrt(Math.Pow(Math.Abs(Point2.X - Point1.X), 2) +
+                             Math.Pow(Math.Abs(Point2.Y - Point1.Y), 2));
+        }
+
+        /**
+         * @return  The slope of the line
+         */
+        public double ComputeSlope()
+        {
+            return (Point2.Y - Point1.Y) / (Point2.X - Point1.X);
+        }
+    }
+}