delegates/2/Application.cs - The static method Compose in class Application.

Lecture 6 - slide 7 : 20 Program 3

using System;

public class Application {

  public delegate double NumericFunction(double d);

  public static NumericFunction Compose                           
                   (NumericFunction f, NumericFunction g){        
    return delegate(double d){return f(g(d));};                   
  }   

  public static void PrintTableOfFunction
                   (NumericFunction f, string fname, 
                    double from, double to, double step){
    double d;

    for(d = from; d <= to; d += step){
     Console.WriteLine("{0,35}({1,-4:F3}) = {2}", fname, d, f(d));
    }

    Console.WriteLine();
  }

  public static double Square(double d){
    return d*d;
  }

  public static double Cubic(double d){
    return d*d*d;
  }

  public static double Minus3(double d){
    return d-3;
  }

  public static void Main(){
    PrintTableOfFunction(Compose(Cubic, Minus3),                
                         "Cubic of Minus3", 0.0, 5.0, 1.0);     

    PrintTableOfFunction(                                       
      Compose(Square, delegate(double d){                       
                       return d > 2 ? -d : 0;}),
      "Square of if d>2 then -d else 0", 0.0, 5.0, 1.0);
  }
}