template classes and types

[megabyte]

Hello,
Can anybody please tell me what I'm doing wrong here. When I do something like:

template<class T> 
class MyNode
{
  public:
    
    MyNode(){key=-1;}
    friend class MyClass;  
   private :
    T info;
    int key; 
 
   
};

template<class T>
class MyClass
{
  public:
    MyClass(){count=0; }
     
  private:
    MyNode Myarray [Item_Max];
    int count;
};

I get an error message saying: syntax error before `[' token
in the line: MyNode Myarray [Item_Max];
while it runs normal when I do something like T Myarray[Item_Max];
What I need is an array of type MyNode but I seem to be confusing the types there
Thanks in advance,
Sofia.

[Graham]

Try this:

template<class T> 
class MyNode
{
  public:
    
    MyNode(){key=-1;}
    friend class MyClass;  
   private :
    T info;
    int key; 
 
   
};

template<class T>
class MyClass
{
  public:
    MyClass(){count=0; }
     
  private:
    MyNode<T> Myarray [Item_Max];   // <<<-------------
    int count;
};

[Graham]

Oh, and use std::vector rather than a fixed array...

[megabyte]

Thanks Graham. I could have sworn that I tried that but I guess I didn't
I have to use an array as I can't insert in a vector of size i.e 10 in position 12. It gets messy everytime I start pushing back in the vector when i have to insert to a position that doesn't exist yet.
Thanks again.
Sofia

[megabyte]

sorry to bother you again but I'm really stuck as I see no reason for the errors I've been having. Using the same class prototypes I have posted before with the correction from Graham i declare in my main() the following: MyClass <int> Myobj;
but I get a bunch of errors that I don't fully understand:
C:/prog/sofia.cpp: In instantiation of `MyNode<int>':
C:/prog/sofia.cpp:27: instantiated from `MyClass<int>'
C:/prog/sofia.cpp:38: instantiated from here
C:/prog/sofia.cpp:13: ` struct MyClass' redeclared as different kind of symbol
C:/prog/sofia.cpp:27: previous declaration of `template<class T> class MyClass'

Can anybody clear this for me please.
Thanks a bunch,
Sofia.

[Kheun]

// Forward declaration
template <class T>
class MyClass;

template<class T> 
class MyNode
{
  public:
    
    MyNode(){key=-1;}
    friend class MyClass<T>;
   private :
    T info;
    int key; 
 };


// Need to declare Item_Max somewhere.
const int Item_Max=10;

template<class T>
class MyClass
{
  public:
    MyClass(){count=0; }
     
  private:
    MyNode<T> Myarray [Item_Max];
    int count;
};

[Graham]

Originally posted by megabyte
<snip>
I have to use an array as I can't insert in a vector of size i.e 10 in position 12. It gets messy everytime I start pushing back in the vector when i have to insert to a position that doesn't exist yet.
Thanks again.
Sofia

Have you investigated std::vector::resize()?

[megabyte]

Thanks a lot Kheun! I really appreciate it.
That <T> in friend class MyClass<T>; saved me a lotta Aspirin

Thanks for the tip Graham, I've knew that resize existed but thought that it was used only to resize down and not to fill up a vector as well.Now that I know I can use it, I tried to use a vector in my program but then I have no idea how the syntax should be as I'm getting the same problems I had with MyNode<T> Myarray [Item_Max];
How would I use a vector instead of an array here? I try vector<MyNode> MyVector; but then I know that the <T> should go somewhere
Any help would be really appreciated.
Sofia.

[Graham]

std::vector<MyNode<T> > My Vector;

The space between the two ">"s is important.