C++: expected identifier before numeric constant

Question

I\'m trying to write a small program using MTL, but I\'m getting the mentioned error when I try to make a MTL Matrix a member of a class.

#include 

        

Answer 1

You can't initialize variable within the class scope, you need to do it in a constructor. Change this:

class myClass
{
private:
    mtl::dense2D<double> Ke(6,6);
};

to this --

class myClass
{
public:
    myClass() : Ke(6,6) { }
private:
    mtl::dense2D<double> Ke;
};

Answer 2

You need to do that in the constructor's initialiser list.

class myClass {
    mtl::dense2D<double> Ke;
public:
    myClass() : Ke(mtl::dense2D<double>(6, 6)) { }
};

Answer 3

Because when you declare

mtl::dense2D<double> Ke;

you're only supposed to declare it, not create it yet. This is the constructor's job in C++:

class myClass
{
public:
    myClass() // constructor
        : Ke(6, 6) // here we use the constructor initializer
    {
    }
private:
    mtl::dense2D<double> Ke; // declaration
};