Chapter review

For review, the complete version of the Default.aspx.cs file for this chapter, including comments, is shown in the following code block:

//using is a directive
//System is a name space
//name space is a collection of features that our needs to run
using System;
using System.Collections.Generic;
using System.Threading;
//public means accessible anywhere
//partial means this class is split over multiple files
//class is a keyword and think of it as the outermost level of grouping
//:System.Web.UI.Page means our page inherits the features of a Page
public partial class _Default : System.Web.UI.Page
{
    private void ShowSquare(double x) => 
    sampLabel.Text += "<br>" + (x * x);//expression bodied function
    protected void Button1_Click(object sender, EventArgs e)
    {
        //make list of double values
        List<double> vals = 
        new List<double>(new double[] { 1, 2, 4, 5, 6, 8 });
        //call ShowSquare on each value inside the list
        vals.ForEach(ShowSquare);
        sampLabel.Text += "<br>-----------------------------------" ;
        //lines 21-24 define an unnamed method, which is applied to each 
        //value in the list
        vals.ForEach(delegate (double x)
        {
            sampLabel.Text += "<br>" + Math.Pow(x, 3);
        });
        sampLabel.Text += "<br>-----------------------------------" ;
        //lines 28-35 create a thread object, and an unnamed method inside
        //it that spawns
        //a thread of processing separate from the "main" program
        Thread td = new Thread(delegate ()
        {
            List<double> arrs = 
            new List<double>(new double[] { 1, 4, 5, 3, 53, 52 });
            arrs.Sort();
            arrs.ForEach(x => sampLabel.Text += $"<br>{x}");
        });
        //start the thread
        td.Start();
        td.Join(); //this is needed to ensure that the thread 
        //"td" runs, and then joins back to the
        //current, main thread, so the program finishes running
    }
}