Thanks very much TATWRTH for your help.
I am very sorry for getting back late.
I am developing a web application in asp.net.
So, I copied RandomTrial class to my App_Code folder, then I copied the content of TestSix() to my Default.aspx page with a modification of
Console.WriteLine(display); to Response.Write(display);
and when I run the application the system will generate six treatments like this:-