使用指针访问对象的类 [英] Classes accessing each other with pointers

问题描述

我仍然对指针感到困惑，也许你可以告诉我一些。

我有一些类指向对方，没有得到以正确的方式访问它们。

  #include< vector> 
 #include< iostream> 
 
 class Player; 
 class Trainer; 
 class Team {
 Trainer * trainer_; 
 std :: vector< Player *> player_; 
 public：
 std :: vector< Player *> player（）; {return player_; } 
 Trainer * trainer（）{return trainer_; } 
 
 std :: vector& lt; Player *> get_playerlist（）{
 return player_; 
}; 
}; 
 
 class Player {
 public：
 
 void setteam_（Team * x）{
 team_ = x; 
} 
 private：
 Team * team_; 
}; 
 
类培训师{
 Team * Team_; 
}; 
 int main（）
 {
玩家player1; 
团队team1; 
 std :: vector< Player *>播放器列表
 player1.setteam _（& team1）; 
 playerlist = team1.get_playerlist（）; 
 std :: cout<< playerlist.size（）; 
 std :: cin.get（）; 
 return 0; 
} 
  

主要有player1创建并分配给team1的播放器列表他应该以某种方式出现在那里，当我得到播放器列表。但是这个代码的输出是1号球员的播放器列表的大小仍然为0.我做错了什么？

解决方案

  player1.setteam _（& team1）;接下来会发生什么：
 
 
 <$ p 
 
 
 
 
 
 
 $ b 
  void setteam_（Team * x）{
 team_ = x; 
} 
  

这里你说这个 c $ c>有指向 Team 的指针设置为与 x 相同的地址。但这并不意味着 Team 对象在 std :: vector 中有指向玩家的指针。这不是自动发生的，你需要类似的：

  void setteam_（Team * x）{
 team_ = X; 
 x-> addPlayer（this）; // add to vector 
} 
  




I'm still confused with pointers, maybe you could enlighten me a bit.

I'm having some classes pointing to each other and don't get the way to access them in the right way.

#include <vector>
#include <iostream>

class Player;
class Trainer;
class Team {
    Trainer* trainer_;
    std::vector<Player*> player_;
public:
    std::vector<Player*> player() { return player_; }
    Trainer* trainer() { return trainer_; }

    std::vector<Player*> get_playerlist(){
        return player_;
    };
};

class Player {
public: 

    void setteam_(Team* x){
        team_ = x;
    }
    private:
    Team* team_;
};

class Trainer {
    Team* Team_;
};
int main()
{
    Player player1;
    Team team1;
    std::vector<Player*> playerlist;
    player1.setteam_(&team1);
    playerlist = team1.get_playerlist();
    std::cout << playerlist.size();
    std::cin.get();
    return 0;
}

In the main there is player1 created and assigned to the playerlist of team1, now he should somehow appear there when i get the playerlist. But the output of this code is that the size of the playerlist of team 1 is still 0. What did I do wrong ?

解决方案

player1.setteam_(&team1);

What happens next is:

void setteam_(Team* x){
    team_ = x;
}

Here you are stating that this Player has pointer to Team set to the same address as x. But this doesn't mean that this Team object has pointer to player in std::vector. This doesn't happen automaticly, you need something like:

void setteam_(Team* x){
    team_ = x;
    x->addPlayer( this);  // add to vector
}

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