Thread: Cannot Instantiate Object from Templated Class

I have a Matrix Class defined as follows:

Code:

#include "matrix.h"

template <class Object>
Matrix<Object>::Matrix(int row, int col)
{
    rows = row;
    cols = col;
    array.resize(row);
    for(int r = 0; r < row; r++){
        array[r].resize(col);
    }
}


template <class Object>
void Matrix<Object>::setValue(Object value, int r, int c)
{
    array[r,c] = value;
}


template <class Object>
Object Matrix<Object>::GetValue(int r, int c) const
{
    return array[r][c];
}


template <class Object>
int Matrix<Object>::GetRow() const
{
    return rows;
}


template <class Object>
int Matrix<Object>::GetCol() const
{
    return cols;
}


template <class Object>
void Matrix<Object>::OutPut(ostream& out) const{
    for(int i = 0; i < rows; i++){
        for(int j = 0; j < cols; i++){
            cout << array[rows][cols] << " ";
        }
    cout << endl;
    }
}

Together with its interface:

Code:

#ifndef MATRIX_H
#define MATRIX_H


#include <iostream>
#include <vector>


using namespace std;


template <class Object>
class Matrix{
public:
    Matrix(int row = 0, int col = 0);
    void setValue(Object value, int r, int c);
    Object GetValue (int r, int c) const;
    int GetRow() const;
    int GetCol() const;
    void OutPut(ostream& out) const;
private:
    vector< vector<Object> > array;
    int rows;
    int cols;
};


#endif // MATRIX_H

Using a driver programme, I cannot for the life of me instantiate the Matrix object:

Code:

#include <iostream>
#include "matrix.h"


using namespace std;


int main(){
    Matrix<int> matrix(2, 2);
    return 0;
}

I have a compilation error that says undefined reference to 'Matrix<int>::Matrix(int, int)' and have no clue how to solve this.

Any clues?

Do you realize that templates are usually header only implementations because both the definition and the implementation must be in the same compilation unit?

Things that will come up once you put the templates in the header file where they belong:

Code:

template <class Object>
void Matrix<Object>::setValue(Object value, int r, int c)
{
    array[r,c] = value;
}

Commas inside brackets probably aren't what you want here.

Code:

template <class Object>
void Matrix<Object>::OutPut(ostream& out) const{
    for(int i = 0; i < rows; i++){
        for(int j = 0; j < cols; i++){
            cout << array[rows][cols] << " ";
        }
    cout << endl;
    }
}

You aren't using i and j inside your loop.

See! I told you they would come up.

OH MY WORD EMBARRESING. Sorry you were right tabstop.

There are no more errors

I feel like an idiot. You basically fixed the error before I asked the question, thats a first ive ever seen on a forum.