Mine

//Entity.h
#ifndef __ENTITY_H
#define __ENTITY_H

#include <iostream>

class Entity {
public:
	Entity(std::string const &_Name);
	~Entity();
	
	std::string GetName();
	int SetName(std::string const &_Name);
protected:
	std::string Name;
	static int ID;
private:
	int IDCount = 0;
};
// ID counter and ID for each entity;
#endif

// entity.cpp
#include <iostream>
#include "Entity.h"

using namespace std;

Entity::Entity(std::string const &_Name) {
	this->SetName(_Name);
	ID = IDCount;
	++IDCount;
}

Entity::~Entity() { }

std::string Entity::GetName() {
	return Name;
}

int Entity::SetName(std::string const &_Name) {
	if(_Name.length > 0 && _Name.length < 50) {
		Name = _Name;
		return 0;
	} else {
		return -1; // Name is too long
	}
}