C++ declaring a const function in header and implementing it in .cpp

Question

I have the following header:

#include <string>

using namespace std;

enum COLOR {Green, Blue, White, Black, Brown};


class Animal{
    private:
    string _name;
    COLOR _color;

    public:
    Animal();
    ~Animal();
    void speak() const;
    void move() const;
} ;

And the following .cpp implementation:

#include <iostream>
#include <string>
#include "Animal.h"
Animal::Animal(): _name("unknown")
    {
        cout << "constructing Animal object" << endl;
    };
Animal::~Animal()
    {
        cout << "destructing Animal object" << endl;
    }
void Animal::speak()
    {
        cout << "Animal speaks" << endl;
    }
void Animal:: move(){};

However, the speak() and move() functions are giving me an error: "no declaration matches Animal::speak()" . If I remove the 'const' at the tail of the declaration, there are no issues in compilation. How do I correctly implement a const function in a .cpp file?

Answer 1

You forget to put const in the implementation.

Change your code to:

void Animal::speak() const
{
    cout << "Animal speaks" << endl;
}
void Animal::move() const {};