안녕하세요 질문입니다

#pragma once

#include <string>
#include "Position2D.h"

class Monster
{
private:
	std::string m_name; // char * data, unsigned length;
	Position2D m_location;
	//int m_x; // location
	//int m_y;

public:
	Monster(const std::string name_in, const Position2D & pos_in)
		:m_name(name_in), m_location(pos_in)
	{

	}

	//void moveTo(const int &x_target, const int &y_target)
	//{
	//	m_x = x_target;
	//	m_y = y_target;
	//}

	void moveTo(const Position2D &pos_target) 
	{
		//m_x = x_target;
		//m_y = y_target;
		m_location.set(pos_target);
	}

	friend std::ostream &operator << (std::ostream &out,  Monster &monster)
	{
		out << monster.m_name << " " << monster.m_location << std::endl;
		return out;
	}

};

값 변경이 안되게 하는거 같은데 상수화하는것 같은데

moveTo 함수 내에서 파라미터로 const를 빼면 왜 안되는것인지 궁금합니다

operator << 함수에선 const 를 안붙여도 되는건가요?

그리고

#pragma once

#include <iostream>

class Position2D

{
private:
	int m_x;
	int m_y;

public:
	Position2D(const int& x_in, const int & y_in)
		:m_x(x_in), m_y(y_in)
	{}

	// TODO: overload operator =

	void set(const Position2D & pos_target) // 파라미터 왜 const
	{
		set(pos_target.m_x, pos_target.m_y);
		// m_x = pos_target.m_x;
		// m_y = pos_target.m_y;
	} 

	void set(const int &x_target, const int &y_target)
	{
		m_x = x_target;
		m_y = y_target;
	}

	friend std::ostream &operator << (std::ostream &out, Position2D &Position2D)
	{
		out <<  Position2D.m_x << " " << Position2D.m_y << std::endl;
		return out;
	}
};

마찬가지로 여기선 operator << 함수에 파라미터중 Position2D에 const를 안붙여도되나요?

너무 헷갈리는데 어디부분을 복습해야할까요..