oop tutorials

[Jesse Phillips]

On Tue, 04 Mar 2008 16:56:15 +0100, Saaa wrote:

> Could anybody give a simple example of unallocated class reference use?
> I think that would explain it all to me :)

class Bike {
    Human owner;

    this(Human o) {
         owner = o;
    }
    public void newOwner(Human o) {
         owner = o;
    }
}

class Human {
    Bike bike;
    char[] name;

public:
   this(char[] n) { name = n; }

    void ride() {
         if(bike !is null) {
             writefln("%s is riding his bike", name);
         }
    }

    void purchase(Bike b) {
         b.newOwner(this);
    }
}

void main() {
    auto store = new Bike[10];
    store[] = new Bike(null);

    Human joe = new Human("Joe");
    joe.ride();

    // Joe buys a new bike
    joe.purchase(store[4]);
}

you will notice that the bike requires an owner, but I provided none 
during creation. Also note that a Human does not have to own a bike, 
would you want to force a creation of bike even though he has not 
purchased one? I didn't test the code, but I hope it works.

One of the things that happens as that you want a reference to an object 
type, but not create a new one, because later you will be getting the 
reference from somewhere else. Feel free to use what I have given you.