I find classes a little difficult to understand an I have some questions:
1. What is the role of the constructor (and destructor)?
2. Does the constructor's name have to be the same with the class?
3. If I have a derivated class (subclass) its constructor must include the arguments of the base class?
Thanks.

1. Ok, when you create a class and then create an instance of that class, it is created in memory, exacally like a normal variable is. When this new instance of a class is created, the constructor is automatically called. Its sort of like (but not exacally) a function. Its normally used to set up member variables with acceptable data. The destructor is the opposite of the constructor. when the program finishes, the destructor automatically deletes the object from memory.

2. yes, and the destructor must be named the same as the class but prefixed with the tilda charactor (~)

3. why would you want to give the constructor arguments?
if you use accessor functions to change class members, you should have no need for passing values to the constructor.

Marc

1)Constructors initialize instance variables
2)Yes
3)No

class myClass
{
private:
int i,j,k;
public:
myClass(){} //Default constructor (must defined when other constructors are used)
myClass(int i, int k) //Overloaded constructor
myClass(int i, int j, int k) //Another overloaded constructor
}


void main()
{
myClass myObject1(); //using default constructor
myClass myObject2(10,5); //using overloaded constructor 1
myClass myObject3(15,10,5); //using overloaded constructor 2
}

Ooops, forgot the implementation of the constuctors:

class myClass
{
private:
int i,j,k;
public:
myClass(){} //Default constructor (must defined when other constructors are used)
myClass(int i, int k) //Overloaded constructor
{
this.i = i;
this.k = k;
}
myClass(int i, int j, int k) //Another overloaded constructor
{
this.i = i;
this.j = j;
this.k = k;
}
}

the word "this" is the instance, CodeRed?

I think this is a pointer to the current instance, so CodeRed's this.blah's should be this->blah's instead.

No, it works my way (I'm not saying your way is wrong, but it does work my way)

-Originally Posted by metamorphic-
"3. why would you want to give the constructor arguments?"

Because that is the ENTIRE purpose of constructors!

yeah i forgot constructors were ment to be dynamic. I was thinking when the constructor was called that default data was entered. I forgot that default data doesnt just mean '0' :). thanks for reminding me

CodeRed, your code doesn't compile in VC++. I'm reasonably close to 100% sure it won't work in any common C++ compiler.

You're right, I was thinking java, my apologies gian

I believe you were referring to Psion.

Although, it *is* nice to hear you apologise every once and a while.