Templates and Unresolved Externals

I'm not sure why I am getting unresolved externals. These are the errors I get:

1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall Array<int,10>::~Array<int,10>(void)" (??1?$Array@H$09@@QAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall Array<int,10>::getSize(void)const " (?getSize@?$Array@H$09@@QBEHXZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall Array<int,10>::Array<int,10>(void)" (??0?$Array@H$09@@QAE@XZ) referenced in function _main
1>F:\Users\yohosuff\Desktop\C++ HTPE10\Debug\C++ HTPE10.exe : fatal error LNK1120: 3 unresolved externals

Here's the code:

Code:

---

#ifndef ARRAY_H
#define ARRAY_H
#include <iostream>
using std::ostream;
using std::istream;

template<typename T, int numberOfElements>
class Array
{
        friend ostream &operator<<( ostream &, const Array<T,numberOfElements> & );
        friend istream &operator>>( istream &, Array<T,numberOfElements> & );     
public:
        Array();
        ~Array();         
        int getSize() const;
        const Array &operator=( const Array & );
        bool operator==( const Array & ) const;

        bool operator!=( const Array &right ) const               
        {                                                         
                return ! ( *this == right );
        }                             
       
        T &operator[]( int );                                             
       
        T operator[]( int ) const;                         
private:
        int size;
        T *ptr;
};
#endif

---

Code:

---

#include <iostream>
using std::cerr;
using std::cout;
using std::cin;
using std::endl;
#include <iomanip>
using std::setw;
#include <cstdlib>
using std::exit;

#include "Array.h" // Array class definition


template<typename T, int numberOfElements>
Array<T,numberOfElements>::Array()
{
        size = ( numberOfElements > 0 ? numberOfElements : 10 );
        ptr = new T[ size ];
        for ( int i = 0; i < size; i++ )
                ptr[ i ] = 0;
}


template<typename T, int numberOfElements>
Array<T,numberOfElements>::~Array()
{
        delete [] ptr;
}

template<typename T, int numberOfElements>
int Array<T,numberOfElements>::getSize() const
{
        return size;
}

template<typename T, int numberOfElements>
const Array<T,numberOfElements> &Array<T,numberOfElements>::operator=( const Array<T,numberOfElements> &right )
{
        if ( &right != this )
        {
               
                if ( size != right.size )
                {
                        delete [] ptr;
                        size = right.size;
                        ptr = new T[ size ];
                }
                for ( int i = 0; i < size; i++ )
                        ptr[ i ] = right.ptr[ i ];
        }
        return *this;
}

template<typename T, int numberOfElements>
bool Array<T, numberOfElements>::operator==( const Array<T,numberOfElements> &right ) const
{
        if ( size != right.size )
                return false;
        for ( int i = 0; i < size; i++ )
                if ( ptr[ i ] != right.ptr[ i ] )
                        return false;
        return true;
}

template<typename T, int numberOfElements>
T &Array<T, numberOfElements>::operator[]( int subscript )
{
        if ( subscript < 0 || subscript >= size )
        {
                cerr << "\nError: Subscript " << subscript
                        << " out of range" << endl;
                exit( 1 );
        }
        return ptr[ subscript ];
}


template<typename T, int numberOfElements>
T Array<T,numberOfElements>::operator[]( int subscript ) const
{

        if ( subscript < 0 || subscript >= size )
        {
                cerr << "\nError: Subscript " << subscript
                        << " out of range" << endl;
                exit( 1 );
        }

        return ptr[ subscript ];
}


template<typename T, int numberOfElements>
istream &operator>>( istream &input, Array<T,numberOfElements> &a )
{
        for ( int i = 0; i < a.size; i++ )
                input >> a.ptr[ i ];

        return input;
}


template<typename T, int numberOfElements>
ostream &operator<<( ostream &output, const Array<T,numberOfElements> &a )
{
        int i;

        for ( i = 0; i < a.size; i++ )
        {
                output << setw( 12 ) << a.ptr[ i ];

                if ( ( i + 1 ) % 4 == 0 )
                        output << endl;
        }

        if ( i % 4 != 0 )
                output << endl;

        return output;
}

---

Code:

---

#include <iostream>
#include <string>
#include <iomanip>
#include <cmath>
#include <ctime>
#include <vector>

using namespace std;

#include "Array.h"

int main()
{

        //14.7
        Array<int,10> a;
        a.getSize();

        //********************
        cout << "\nProgram Execution Complete\n";
        system("PAUSE");
        return 0;
}

---

Any help would be appreciated! :)

You have to move the code from your template implementatation file into the header or #include it from the header.
Reason: at the point of instantiation of a template the compiler has to be able to see the implementation.
Search the forum for a better explaination. This problem comes up rather frequently.
Kurt

and here's the link to Zuk's explaination.
Why do I get linker errors when I use template friends?

Thanks for the tips, I'll give it a shot.

Awesome! Placing the implementation of the class in the header file worked! And, potatoCode, that link you provided was very helpful. Very helpful indeed. Kudos!