public static void Questions()
{
// class Person { }
Person me = new Person();
Person you = new Person();
//Q. how many people are there?
//... ie. how many values (object) of the type Person are there?
//A. 2
// class Detective : Person {}
Detective holmes = new Detective();
Detective marple = new Detective();
//Q. how may people are there?
//A. 4
System.Console.WriteLine(holmes is Detective);
System.Console.WriteLine(me is Detective);
System.Console.WriteLine(holmes is Person);
System.Console.WriteLine(holmes.GetType().Name);
}
public static void Relationships()
{
Person me = new Person();
Person you = new Person();
/*
* me and you belong to the class Person
* the type 'Person' denotes the set {me, you}
* 'new Person' adds an element (a person) to the set
*
* cf. bool means {true, false}, int means {-2^32, ..., 0, ..., 2^32 - 1}
*/
Detective sherlock = new Detective();
Doctor watson = new Doctor();
System.Console.WriteLine(sherlock is Person);
System.Console.WriteLine(sherlock is Detective);
System.Console.WriteLine(watson is Person);
System.Console.WriteLine(watson is Doctor);
// 'is' expression's given expression is never of the provided type
System.Console.WriteLine(watson is Detective);
// 'is' expression's given expression is never of the provided type
//c. objects however have one 'cannonical' type, the type they were made from
//ie., the type new'd -- even though they belong to multiple
System.Console.WriteLine(sherlock.GetType().Name);
System.Console.WriteLine(watson.GetType().Name);
//d. there are two ways of saying an object belongs to multiple types
//1. if the supertype is an interface = implementation
//2. if the sypertype is a class = inheritance
//NB. supertype is the larger group, ie. the type on the RHS of :
// SubType : SuperType
//let's stop here on the syntax/demos and talk about the concepts...
//syntax revisited / continued
}