How do I initialize the vector I have defined in my header file?

Question

I have the following in my Puzzle.h

class Puzzle
{
    private:
        vector<int> puzzle;
    public:
        Puzzle() : puzzle (16) {}
        bool isSolved();
        void shuffle(vector<int>& );
};

and then my Puzzle.cpp looks like:

Puzzle::Puzzle()
{
    // Initialize the puzzle (0,1,2,3,...,14,15)
    for(int i = 0; i <= puzzle.size(); i++)
    {
        puzzle[i] = i;
    }
}

// ... other methods

Am I using the initializer list wrong in my header file? I would like to define a vector of ints and initialize its size to that of 16. How should I do this?

G++ Output:

Puzzle.cpp:16: error: expected unqualified-id before ')' token
Puzzle.cpp: In constructor `Puzzle::Puzzle()':
Puzzle.cpp:16: error: expected `)' at end of input
Puzzle.cpp:16: error: expected `{' at end of input
Puzzle.cpp: At global scope:
Puzzle.cpp:24: error: redefinition of `Puzzle::Puzzle()'
Puzzle.cpp:16: error: `Puzzle::Puzzle()' previously defined here

Answer 1

You can not define the constructor twice! So in the header file replace

Puzzle() : puzzle (16) {}

by

Puzzle();

And in the .cpp source file add

puzzle.resize(16);

in the first line.

Answer 2

The main problem is you define your constructor twice - once in the header, then again in the cpp file. Remove the one in the header and move the initialization to the cpp:

Puzzle::Puzzle()
: puzzle (16)
{
    // Initialize the puzzle (0,1,2,3,...,14,15)
    for(int i = 0; i <= puzzle.size(); i++)
    {
        puzzle[i] = i;
    }
}

Moreover, unless you are using std::vector - or worse, using namespace std - in your header (which you shouldn't), your vector should be declared like this in the header:

    std::vector<int> puzzle;

Answer 3

The problem is that you have defined Puzzle::Puzzle() in both the header and the .cpp file, so it has two definitions.

The initializer list can go along with the constructor definition in the .cpp file:

Puzzle::Puzzle()
    : puzzle (16)
{
    // ...
}

and remove the definition from the header:

Puzzle(); // I'm just a declaration now, not a definition

Answer 4

You can't initialise something in two different places. In the header, just declare it:

Puzzle();

in the .cpp file define it:

Puzzle::Puzzle() : puzzle( 16 )
{
    // Initialize the puzzle (0,1,2,3,...,14,15)
    for(int i = 0; i < puzzle.size(); i++)
    {
        puzzle[i] = i;
    }
}

though you would probably be better off not using an initialisation list:

Puzzle::Puzzle() 
{
    // Initialize the puzzle (0,1,2,3,...,14,15)
    for(int i = 0; i < 16; i++)
    {
        puzzle.push_back( i );
    }
}