Exercise 5.15
Finding and sorting elements in an array

Make an array of Point objects. You can, for instance, use this version of class Point. You can also use a version that you wrote as solution in one of the previous exercises.

Use the method System.Array.Find to locate the first point in the array that satisfies the following:

The sum of the x and y coordinates are (very close to) zero

The solution involves the programming of an appropriate delegate in C#.

Next use the method System.Array.FindAll to locate all such points.

Finally, sort the list of points by use of the static method System.Array.Sort<Point>(Point[], Comparison<Point>). Point is a type parameter of Sort. You do not need to care much about it in this exercise. We will come back to type parameters in a later lecture. Comparison<Point> is a delegate that compares two points, say p1 and p2. Use a comparison for which

   p1 <= p2 if and only if p1.X + p1.Y <= p2.X + p2.Y

Look up the documentation of Sort and Comparison to find the necessary information.