C++ 试图从另一个类访问变量_C++

C++ 试图从另一个类访问变量

c++

C++ 试图从另一个类访问变量,c++,C++,我有一个问题，从我的原始类中获取变量以在另一个类方法中打印我的问题的快速示例：假设变量是在test.h文件中声明的： class player{ private: int x = 10; void setX(); //method for setting X from user input int getX(); //Method for retrieving variable } 然后在另一个类方法中，我想打印X class inTheWoods{ public: printInf

我有一个问题，从我的原始类中获取变量以在另一个类方法中打印我的问题的快速示例：

假设变量是在test.h文件中声明的：

class player{
private:
int x = 10;
void setX(); //method for setting X from user input
int getX(); //Method for retrieving variable
}

然后在另一个类方法中，我想打印X

 class inTheWoods{
 public:
 printInfo();
 }

test.cpp文件：

void player::setX(){
cout << "Set X to a number:" << endl;
cin >> x
}

int player::getX(){
return x;
} 


int inTheWoods::printInfo(){
player playerObj; //Player object to access methods in player class
cout << playerObj.getX();
}

每当我运行类似于这个问题的程序时，int不能正确显示，并抛出一个奇怪的负数。我希望这不是太多的代码，并且我正确地记录了所有内容

如果您希望这些类位于单独的文件中，那么它仍然可以工作：

Main.cpp

#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

#包括
#包括“inTheWoods.h”
int main（）
{
伍德索布；
printInfo（）；
返回0；
}

Player.h

#pragma once
#include <iostream>
class Player
{
    int x = 10;
    void setX();
public:
    int getX();
};

//#pragma once
#include "Player.h"
#include <iostream>

class inTheWoods
{
public:
    void printInfo();
};

#pragma once

class player
{
private:
    int m_x;
public:
    player();
    player(const int& x);

    void setX();            //method for setting X from user input
    const int& getX()const; //Method for retrieving variable
};

#pragma once

class inTheWoods
{
public:
    inTheWoods();
    ~inTheWoods();
    void printInfo();
};

#pragma一次
#包括
职业选手
{
int x=10；
void setX（）；
公众：
int getX（）；
};

Player.cpp

#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

#包括“Player.h”
void Player:：setX（）
{
std：：cout x；
}
int-Player:：getX（）
{
返回x；
}

在树林中.h

#pragma once
#include <iostream>
class Player
{
    int x = 10;
    void setX();
public:
    int getX();
};

//#pragma once
#include "Player.h"
#include <iostream>

class inTheWoods
{
public:
    void printInfo();
};

#pragma once

class player
{
private:
    int m_x;
public:
    player();
    player(const int& x);

    void setX();            //method for setting X from user input
    const int& getX()const; //Method for retrieving variable
};

#pragma once

class inTheWoods
{
public:
    inTheWoods();
    ~inTheWoods();
    void printInfo();
};

/#pragma一次
#包括“Player.h”
#包括
森林里的阶级
{
公众：
void printInfo（）；
};

inTheWoods.cpp

#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

#包括“inTheWoods.h”
void inTheWoods:：printInfo（）
{
Player playerbj；//访问Player类中方法的Player对象
std:：cout如果您希望类位于单独的文件中，它仍然可以工作：
Main.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

#包括
#包括“inTheWoods.h”
int main（）
{
伍德索布；
printInfo（）；
返回0；
}

Player.h
#pragma once
#include <iostream>
class Player
{
    int x = 10;
    void setX();
public:
    int getX();
};

//#pragma once
#include "Player.h"
#include <iostream>

class inTheWoods
{
public:
    void printInfo();
};

#pragma once

class player
{
private:
    int m_x;
public:
    player();
    player(const int& x);

    void setX();            //method for setting X from user input
    const int& getX()const; //Method for retrieving variable
};

#pragma once

class inTheWoods
{
public:
    inTheWoods();
    ~inTheWoods();
    void printInfo();
};

#pragma一次
#包括
职业选手
{
int x=10；
void setX（）；
公众：
int getX（）；
};

Player.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

#包括“Player.h”
void Player:：setX（）
{
std：：cout x；
}
int-Player:：getX（）
{
返回x；
}

在树林中.h
#pragma once
#include <iostream>
class Player
{
    int x = 10;
    void setX();
public:
    int getX();
};

//#pragma once
#include "Player.h"
#include <iostream>

class inTheWoods
{
public:
    void printInfo();
};

#pragma once

class player
{
private:
    int m_x;
public:
    player();
    player(const int& x);

    void setX();            //method for setting X from user input
    const int& getX()const; //Method for retrieving variable
};

#pragma once

class inTheWoods
{
public:
    inTheWoods();
    ~inTheWoods();
    void printInfo();
};

/#pragma一次
#包括“Player.h”
#包括
森林里的阶级
{
公众：
void printInfo（）；
};

inTheWoods.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

#包括“inTheWoods.h”
void inTheWoods:：printInfo（）
{
Player playerbj；//访问Player类中方法的Player对象
std:：cout这是一个有效的方法。为了创建具有一些默认值的实例，提供构造函数始终是一个很好的做法。下面的代码有望根据您的要求工作：
main.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

player.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

inTheWoods.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

这是一个有效的方法。为了创建具有一些默认值的实例，提供构造函数始终是一个很好的做法。下面的代码有望根据您的要求工作：
main.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

player.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

inTheWoods.cpp
#include <iostream>
#include "inTheWoods.h"


int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "Player.h"

void Player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> x;
}

int Player::getX()
{
    return x;
}

#include "inTheWoods.h"

void inTheWoods::printInfo()
{
    Player playerObj; //Player object to access methods in player class
    std::cout << playerObj.getX();
}

#include <iostream>
#include "inTheWoods.h"

int main()
{
    inTheWoods woodsObj;
    woodsObj.printInfo();
    return 0;
}

#include "player.h"
#include <iostream>

player::player()              // defualt constructor
    :m_x(0) {}

player::player(const int& x)
    :m_x(x) {}                // parameterised

void player::setX()
{
    std::cout << "Set X to a number:" << std::endl;
    std::cin >> m_x;
}

const int& player::getX()const
{
    return m_x;
}

#include "inTheWoods.h"
#include "player.h"
#include <iostream>
inTheWoods::inTheWoods() {}

inTheWoods::~inTheWoods() {}

void inTheWoods::printInfo()
{
    //Player object to access methods in player class
    player playerObj;      // will beinitialized with 0
    player playerObj2(10); // will beinitialized with 10
    std::cout << playerObj.getX() <<std::endl;
    std::cout << playerObj2.getX() <<std::endl;
}

player
没有构造函数，因此playerObj
的成员会得到不可预测的值。player-playerObj；//player对象来访问player类中的方法
您创建了一个player类型的新局部变量。然后不要对它做任何操作。我希望它会打印10。@PeteBecker在这种情况下如何使用构造函数。他们有点困惑me@drescherjm这是我创建的对象，因此我可以访问该类中的方法。除非这是一种错误的方法，否则如果您想对player对象执行一些有用的操作，则不应在inTheWoods:：printInfo（）中创建局部变量.player
没有构造函数，因此playerObj
的成员会得到不可预测的值。player-playerObj；//player对象来访问player类中的方法
您创建了一个player类型的新局部变量。然后不要对它做任何操作。我希望它会打印10。@PeteBecker在这种情况下如何使用构造函数.他们有点困惑me@drescherjm这是我创建的对象，因此我可以访问该类中的方法。除非这是一种错误的方法，否则如果您想对player对象执行一些有用的操作，则不应在inTheWoods:：printInfo（）中创建局部变量。我已将woods类和player类彼此分离，但仍会遇到相同的错误，即当尝试在其他类方法中打印时，我的私有变量没有值。某些编译器不允许在类级别声明x
。请尝试将x=10
初始化移到常量在这种情况下，我试图从用户输入中设置x，因此将其放入构造函数将不起作用。在这种情况下，将setX（）移动到public并使用playerbj.setX（）调用它
。如果这不起作用，请更清楚地分享您看到的内容。这是我遇到的问题的一个粘贴箱。希望这能让事情更清楚。我已将woods类和player类彼此分离，但仍然会遇到相同的错误，即在尝试打印另一个cl时，我的私有变量没有值ass方法在类级别声明x
时，某些编译器不允许初始化。在这种情况下，请尝试将x=10
初始化移动到构造函数。我正在尝试从用户输入设置x，因此将其放入构造函数将不起作用。在这种情况下，请移动setX（）使用playerbj.setX（）；
公开并调用它。如果这不起作用，请更清楚地分享您看到的内容。这是我遇到的问题的粘贴箱。希望这能让事情更清楚。