cpy ctr issue

Why are you templating with M for the methods and T for the class?

Dave

Problem 1: When you define a templated "copy constructor" and assignment operator, you still need to define the non templated versions for your class, or the compiler will call the default generated ones anyways.

Problem 2: No, don't do that. If you want to you can define assignment in terms of the copy constructor. ex:

A & operator=(const A & other) {  A temp(other);  this->swap(temp); // assuming you have a swap member function}

But doing the opposite can really hose you if the assignment operator assumes a class invariant that isn't true if the member variables are default constructed (which is the state your object will be in just before the assignment is called.

Problem 3: Don't name your variables with an underscore followed by a capital letter. Those identifiers are reserved for the implementation.

Quote:

Original post by SiCrane Problem 1: When you define a templated "copy constructor" and assignment operator, you still need to define the non templated versions for your class, or the compiler will call the default generated ones anyways. Problem 2: No, don't do that. If you want to you can define assignment in terms of the copy constructor. ex: A & operator=(const A & other) { A temp(other); this->swap(temp); // assuming you have a swap member function} But doing the opposite can really hose you if the assignment operator assumes a class invariant that isn't true if the member variables are default constructed (which is the state your object will be in just before the assignment is called. Problem 3: Don't name your variables with an underscore followed by a capital letter. Those identifiers are reserved for the implementation.

Instead of using cpyctr in operator=, will it be good to create a private method that will be used in both, such as:

void copy (const A & other)A & operator (const A & other){  this->copy (other);  return *this}

Also, should I use the templated cpyctr (with M) inside the non templated cpyctr?

I have another problem.
(I will change _ soon)

I have a method defined, but I get compilation error about its implementation:



I get the following compilation error:
error C2248: 'DefensePointer::pInstancesAmount': cannot access private member declared in class 'DefensePointer' with [ T=Sprite ] and [ T=Sprite ]

Why do I get this error? can't I access private members of this?

Quote:

Original post by The C modest god Why do I get this error? can't I access private members of this?

You are trying to access private members of the template instantiated with different template arguments (T vs M). When T and M happen to be the same type, you will not get this error, however, if T and M are different, you have to make sure that the instantiations are friends of each other in order to access each others members. (Edit: It's odd that you are getting that exact error as it seems as though it states that M and T are both "Sprite", so that error shouldn't be happening, unless I'm misreading it)

Inside the class template's definition, put:

template< typename M >friend class DefensePointer;

[Edited by - Polymorphic OOP on August 26, 2006 3:26:08 PM]

Quote:

Original post by Polymorphic OOP Quote: Original post by The C modest god Why do I get this error? can't I access private members of this? You are trying to access private members of the template instantiated with different template arguments (T vs M). When T and M happen to be the same type, you will not get this error, however, if T and M are different, you have to make sure that the instantiations are friends of each other in order to access each others members. (Edit: It's odd that you are getting that exact error as it seems as though it states that M and T are both "Sprite", so that error shouldn't be happening, unless I'm misreading it) Inside the class template's definition, put: template< typename M >friend class DefensePointer< M >;

I didnt understand where exactly I should put this?

Quote:

Original post by The C modest god I didnt understand where exactly I should put this?

template <class T>class DefensePointer {  template <class M>  friend class DefensePointer;/* ... */};