instantiating a class in another class

[madshov]

Hi,
I have made a matrix class, that I wish to make an instiation of in another class.
Matrix class:

#include <vector>
#include <iostream>

using namespace std; // So the program can see cout and endl

class Matrix
{

   //-public member data
   public:
     //-constructor, copy constructor, and deconstructor
     Matrix(const vector< vector<double> > &m);
     Matrix(const Matrix& m);
     ~Matrix();

     //-getter methods
     int get_rows() const;
     int get_cols() const;
     double &value(int row, int col);

  //-private member data
  private:
     vector< vector<double> > mat;
     int columns;
     int rows;
};
/**Constructor*/
Matrix::Matrix(const vector< vector<double> > &m)
:mat(m),rows(m.size()),columns(m[0].size())
{
}
/**Copy Constructor*/
Matrix::Matrix(const Matrix& m)
{
}
/**Deconstructor*/
Matrix::~Matrix()
{
}

second class:

class test
{
	int length;
	double val;
        vector< vector<double> > vect_2d;
        Matrix mat_one;
    
	public:
        //constructor
	test(const int l, Angles angles);
	
        //copy
	test(const test &s);
	
        //destructor
	~test();
	
	void print();
};

test::test(const int l, Angles angles)
{
     vector< vector<double> > vect_2d(3, vector<double>(3,1));  	

     Matrix mat_one(vect_2d);
}

test::~test()
{
}

void test::print()
{
      mat_one.value(1,1);
}

I not able to declare mat_one in the test class, because there is no matching function in the matrix class. But I can't write something like Matrix mat_one(vector< vector<double> >). Any hints? Thanks.

[Banfa]

You need to either, provide Matrix with a default constructor or when you construct you test class specifically call one of the Matrix constructors that are available.

I will assume you know how to provide Matrix with a default constructor.

You can call a specific constructor for a nested class in the same way that you initialise a variable in class constructor, like this

[code=cpp]
test::test(cons t int l, Angles angles)
: mat_one( vector< vector<double> >(3, vector<double>( 3,1)))
{
}
[/code]

This is rather complex, you may wish to consider writing a constructor for Matrix that takes the same parameters as test.