error LNK2019: unresolved external symbol "public: void __thiscall Button::ButtonInit" [duplicate] - c++

Question

This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 7 years ago.
I've been going through a C++/SFML tutorial (http://www.gamefromscratch.com/page/Game-From-Scratch-CPP-Edition.aspx) and, having reached the end, started altering the code to try out various things and get more comfortable both with C++ and SFML.
For the menu screen, I decided to create an object for buttons. To this end I created Button.cpp and Button.h, then linked to Button.h in the MainMenu.h file. I added Button button_play as a public member of class MainMenu, however when I call a Button function (for example: button_play.ButtonInit("new-game");), I receive the error: error LNK2019: unresolved external symbol "public: void __thiscall Button::ButtonInit(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?ButtonInit#Button##QAEXV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std###Z) referenced in function "public: enum MainMenu::MenuResult __thiscall MainMenu::Show(class sf::RenderWindow &)" (?Show#MainMenu##QAE?AW4MenuResult#1#AAVRenderWindow#sf###Z)
I've done a lot of searching around this, and most of the answers I've found revolve around not implementing class member functions correctly, however as far as I can tell I am doing it correctly. I am, however, very new to C++, so it's possible that I'm just missing something.
Here's my code:
MainMenu.h
#pragma once
#include "SFML\Window.hpp"
#include "SFML\Graphics.hpp"
#include "GameObjectManager.h"
#include "Button.h"
#include <list>
class MainMenu
{
public:
MainMenu(){};
~MainMenu() {};
enum MenuResult { Nothing, Exit, Play };
const static GameObjectManager& GetGameObjectManager();
struct MenuItem
{
public:
sf::Rect<int> rect;
MenuResult action;
};
MenuResult Show(sf::RenderWindow& window);
static GameObjectManager _gameObjectManager;
Button button_play;
private:
MenuResult GetMenuResponse(sf::RenderWindow& window);
MenuResult HandleClick(int x, int y);
std::list<MenuItem> _menuItems;
};
MainMenu.cpp (this is quite long; I've only included the function that calls ButtonInit() and the function that Show() returns - if you need to see more, let me know and I can include the rest of the code for this file)
#include "stdafx.h"
#include "MainMenu.h"
#include "ServiceLocator.h"
#include "Button.h"
MainMenu::MenuResult MainMenu::Show(sf::RenderWindow& window)
{
button_play.ButtonInit("new-game");
return GetMenuResponse(window);
}
MainMenu::MenuResult MainMenu::GetMenuResponse(sf::RenderWindow& window)
{
sf::Event menuEvent;
while(42 != 43)
{
while(window.pollEvent(menuEvent))
{
if(menuEvent.type == sf::Event::MouseMoved)
{
button_play.Update(window);
}
if(menuEvent.type == sf::Event::MouseButtonPressed)
{
if(ServiceLocator::GetAudio()->IsSongPlaying())
{
ServiceLocator::GetAudio()->StopAllSounds();
}
return HandleClick(menuEvent.mouseButton.x,menuEvent.mouseButton.y);
}
if(menuEvent.type == sf::Event::Closed)
{
return Exit;
}
}
}
}
Button.h
#pragma once
class Button
{
public:
Button() {};
~Button() {};
void ButtonInit(std::string name);
void Update(sf::RenderWindow & rw);
};
Button.cpp
#include "StdAfx.h"
#include "Button.h"
void Button::ButtonInit(std::string name)
{
}
void Button::Update(sf::RenderWindow & rw)
{
}
stdafx.h (probably don't need to see this, but just in case)
// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//
#pragma once
#include "targetver.h"
#include <stdio.h>
#include <tchar.h>
// TODO: reference additional headers your program requires here
#include <SFML/System.hpp>
#include <SFML/Graphics.hpp>
#include <SFML/Window.hpp>
#include <SFML/Audio.hpp>
#include <map>
#include <iostream>
#include <cassert>
#include <string>
Any help would be appreciated.

Answer 1

I assume, you have both classes in the same project.
The linker-message tells you, that the linker does not find a fitting function definition.
So my guess would be ... the linker cannot find a fitting overload of the function. "new-game" is a const char* and it is not a std::string.
a) change your method signature to
void ButtonInit(const char* name);
or
b) call your method like:
button_play.ButtonInit(std::string("new-game"));