Is it required to define the initialization list in a header file?

Question

Recently I created class Square:

=========header file======

class Square
{
    int m_row;
    int m_col;

public:
    Square(int row, int col): m_row(row), m_col(col) 
};

==========cpp file======

#include "Square.h"

Square::Square(int row, int col)
{
    cout << "TEST";
}

but then I receive lots of errors. If I remove the cpp file and change the header file to:

=========header file======

class Square
{
    int m_row;
    int m_col;

public:
    Square(int row, int col): m_row(row), m_col(col) {};
};

it complies with no errors. Does it mean that initialization list must appear in the header file?

Answer 1

You can have

==============header file ================

class Square
{
    int m_row;
    int m_col;

public:
    Square(int row, int col);
};

==================cpp ====================

Square::Square(int row, int col):m_row(row), m_col(col) 
{}