static void Main(string[] args)
{
// C# has "property initializer" system
var fido1 = new Dog();
fido1.Id = 1;
fido1.Name = "Fido";
fido1.Breed = "German Shepherd";
// Much nicer syntax for doing the same thing!!!
var fido2 = new Dog
{
Id = 1,
Name = "Fido",
Breed = "German Shepherd"
};
fido1.GoTo("park");
fido1.MakeNoise();
// IAnimal is a parent type of Dog
// Dog is a subtype of IAnimal
IAnimal animal = fido1;
// converting from dog variable to IAnimal variable is upcasting
// upcasting is guaranteed to exceed so it is implicit
//when the Dog object is contained in IAnimal Variable,
// we cannot see the Dog-specific stuff anymore
// animal.Breed // error
// Converting from IAnimal to Dog is downcasting and is not guaranteed to succeed
// must be explicit with () casting
Dog dog2 = (Dog)animal;
// not all casting is up/downcasting, e.g. int to double and back
// double to int loses data and thus must be exclicit
int integer = (int)3.4;
// int to double cannot lose data however
// thus can be done implicitly
double num = integer;
var animals = new IAnimal[2];
animals[0] = fido1;
animals[1] = new Eagle
{
Id = 3,
Name = "Bob",
};
foreach (IAnimal item in animals)
{
Console.WriteLine(item.Name);
item.MakeNoise();
item.GoTo("Park"); // here we can't see Eagle.GoTo when using new
// works right when we properly override using virtual and override
}
Eagle eagle1 = (Eagle)animals[1];
eagle1.GoTo("Park");
// camel case for local variables and private fields
//Titlecase for everything else
}