How to create a constructor in source file C++

Solution 1:

You need to declare a default value for your constructor taking a bool if you want it to be usable without arguments. A constructor without any mandatory arguments is a default constructor.

The definition of the class and declaration of its member functions:

#pragma once // or a standard header guard

class Node {
public:
    Node(bool isWord = false); // this is now a default constructor

    // other members etc ...
};

A possible use of it:

#include "Node.h"              // where Node is defined

int main() {
    Node x;                    // default construct a `Node`
}

The definition of the constructor in Node.cpp:

#include "Node.h"
#include <ios>
#include <iostream>

Node::Node(bool isWord) {      // note, no default values here
    std::cout << std::boolalpha << isWord << '\n';
}

Output if compiled and linked:

false

Demo