C++ 组合循环依赖

Question

我正在尝试学习 C++，目前我正在尝试了解如何用这种语言实现 object 组合。

我有一个 Character class 由 Hero 和 Monster class.

继承

一个Character有一个NormalAbility和一个SpecialAbility。

我做了 NormalAbility 和 SpecialAbility classes 并且都继承了 Ability superclass.

我的问题是，当我将#include "Character.h" 放入 Ability.h 时，Character.h 中的 normalAbility 和 specialAbility 变量没有被识别为它们受尊重的 class es。 "syntax error : identifier string" 两个技能继承 classes

的 headers 中显示的错误

这是我的代码：

Character.h

#pragma once
#include <string>
#include "NormalAbility.h"
#include "SpecialAbility.h"

using namespace std;

class Character
{
public:
   Character(string name, string type, int hp, NormalAbility na, 
             SpecialAbility sa);
   bool isDead();
   void damage(int amt);
   void heal(int amt);
   void attack(Character* c, int amt);

private:
   string name;
   string type;
   int hp;
   int maxHp;
   NormalAbility* normalAblity;
   SpecialAbility* specialAbility;
}

Character.cpp

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

Character::Character(string name, string type, int hp, NormalAbility* na, 
             SpecialAbility* sa)
{
   this->name = name;
   this->type = type;
   this->maxHp = hp;
   this->hp = hp;
   normalAbility = na;
   specialAbility = sa;
}

bool Character::isDead(){
   return hp <= 0;
}

void Character::damage(int amt){
   if (hp > 0){
      hp -= amt;
   }
   else{
      hp = 0;
   }
}

void Character::heal(int amt){
   if (hp + amt > maxHp){
      hp = maxHp;
   }
   else{
      hp += amt;
   }
}

void Character::attack(Character* c, int amt){
   c->damage(amt);
}

Hero.h

#pragma once
#include "Character.h"
#include <string>

using namespace std;

class Hero :
   public Character
{
public:
   Hero(string name, int hp);
}

Hero.cpp

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

Hero::Hero(string name, int hp) 
     : Character(name, "Hero", hp)
{
}

Ability.h

#pragma once
#include <string>
#include "Character.h"

using namespace std;

class Ability
{
public:
   Ability(string name, string type, Character* owner);
   void levelUp();
private:
   string name;
   string type;
   int level;
   Character* owner;
}

Ability.cpp

#include "Ability.h"

Ability::Ability(string name, string type, Character* owner)
{
   this->name = name;
   this->type = type;
   this->owner = owner;
   level = 1;
}

void Ability::levelUp(){
   level++;
}

NormalAbility.h

#pragma once
#include "Ability.h"
#include <string>

using namespace std;

class NormalAbility :
   public Ability
{
public:
   NormalAbility(string name);
}

NormalAbility.cpp

#pragma once
#include "NormalAbility.h"
#include <string>

using namespace std;

NormalAbility::NormalAbility(string name) : Ability(name, "Normal")
{
  //some codes
}

Answer 1

这样您就可以避免循环包含 .h 文件，因为您将其包含在 .cpp 中，而在 .h 中您是说 "Character exists but don't care about his definition right now"

Ability.h

#pragma once
#include <string>


class Character;

using namespace std;

class Ability
{
public:
   Ability(string name, string type, Character* owner);
   void levelUp();
private:
   string name;
   string type;
   int level;
   Character* owner;
}

Ability.cpp

#include "Ability.h"
#include "Character.h"

Ability::Ability(string name, string type, Character* owner)
{
   this->name = name;
   this->type = type;
   this->owner = owner;
   level = 1;
}

void Ability::levelUp(){
   level++;
}

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