Question

所以我有这个代码应该基本上创建对象，然后将它们发送到'arena'，它通过cout输出一串文本。我遇到的问题是我的主要问题是当我尝试发送创建的对象时，我遇到了错误，我可以使用一些解释，所以我理解我做了什么/做错了什么。我理解（大多数情况下）使用对象，但是当我开始使用*时，我有点困惑。我得到的问题是在说明Engine-＆gt;竞技场的行的myGame.cpp中。

代码：

Engine.h

#ifndef ENGINE_CLASS
#define ENGINE_CLASS

#include <string>
using namespace std;

class Engine
{

public:
    Engine();
    ~Engine();
    void arena(Character*, Character*);

};

class Character
{

private:
    string m_name;

public:
    Character();
    ~Character();
    virtual void fight();
    virtual string getName();
    virtual void setName(string);

};

class Gladiator : public Character
{

public:
    Gladiator();
    ~Gladiator();
    virtual void fight();
    virtual string getName();
    virtual void setName(string);

};

class Monster : public Character
{

public:
    Monster();
    ~Monster();
    virtual void fight();
    virtual string getName();
    virtual void setName(string);

};

#endif

Engine.cpp

#include <iostream>
#include "Engine.h"
using namespace std;


//Methods for Engine Class
Engine::Engine()
{

}

Engine::~Engine()
{

}

void Engine::arena(Character *oCharacter1, Character *oCharacter2)
{
    //Logic
    oCharacter1->fight();
    oCharacter2->fight();
    //More Logic
}

//Methods for Parent-Charachter Class
Character::Character()
{
    m_name = "Unknown";
}

Character::~Character()
{
    m_name = "";
}

void Character::fight()
{
    cout << "Fight" << endl;
}

string Character::getName()
{
    return m_name;
}

void Character::setName(string newName)
{
    m_name = newName;
}

//Methods for Child-Gladiator Class
Gladiator::Gladiator()
{
    Character::setName("Maximus");
}

Gladiator::~Gladiator()
{
    Character::setName("");
}

void Gladiator::fight()
{
    cout << "Maximus strikes monster..." << endl;
}

string Gladiator::getName()
{
    return Character::getName();
}

void Gladiator::setName(string newName)
{
    Character::setName(newName);
}

//Methods for Child-Monster Class
Monster::Monster()
{
    Character::setName("Monster");
}

Monster::~Monster()
{
    Character::setName("");
}

void Monster::fight()
{
    cout << "Monster strikes Maximus..." << endl;
}

string Monster::getName()
{
    return Character::getName();
}

void Monster::setName(string newName)
{
    Character::setName(newName);
}

myGame.cpp

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

using namespace std;

int main()
{

    //Instantiation
    Engine engine;
    Character *aCharacter1;
    Character *aCharacter2;

    //Association
    aCharacter1 = new Gladiator;
    aCharacter2 = new Monster;

    //Fight
    Engine->arena(*aCharacter1, *aCharacter2);

    //Cleanup
    delete aCharacter1;
    delete aCharacter2;

}

更新

现在考虑到更正，我得到以下4个错误

Error   1   error C2061: syntax error : identifier 'Character'  c:\users\christopher\desktop\paul\school\neit\game architecture\week 4 & 5\christopher-midtermpart2\christopher-midtermpart2\engine.h   13  1   Christopher-MidtermPart2

Error   3   error C2061: syntax error : identifier 'Character'  c:\users\christopher\desktop\paul\school\neit\game architecture\week 4 & 5\christopher-midtermpart2\christopher-midtermpart2\engine.h   13  1   Christopher-MidtermPart2

Error   4   error C2511: 'void Engine::arena(Character *,Character *)' : overloaded member function not found in 'Engine'   c:\users\christopher\desktop\paul\school\neit\game architecture\week 4 & 5\christopher-midtermpart2\christopher-midtermpart2\engine.cpp 18  1   Christopher-MidtermPart2

Error   2   error C2660: 'Engine::arena' : function does not take 2 arguments   c:\users\christopher\desktop\paul\school\neit\game architecture\week 4 & 5\christopher-midtermpart2\christopher-midtermpart2\mygame.cpp 19  1   Christopher-MidtermPart2

Answer 1

你的void arena(Character*, Character*);方法会将poiters指向Character，但是你试图通过指针传递实际对象：
Engine->arena(*aCharacter1, *aCharacter2);
将此行更改为
Engine->arena(aCharacter1, aCharacter2); 或更改您的方法，因此它可以将对象作为参数而不是指针：
void arena(Character, Character);

另外，如Giulio Franco所述：
arena is an instance method. You cannot call it on a class. It's engine.arena, not Engine->arena，PaulMcKenzie提及：
Undefined behavior when you call delete on your objects. Your base class destructor is not declared as virtual

Answer 2

1）将Character析构函数声明为virtual。

原因是在main中，您正在通过基类指针删除指向派生对象的指针。一旦你这样做，基类必须有一个声明为virtual的析构函数，否则行为是未定义的。

所以你需要这个：

virtual ~Character();

然后在main中，现在已经定义了行为：

//Cleanup
delete aCharacter1;
delete aCharacter2;

2）你必须将指针传递给arena函数，而不是对象。

engine.arena(aCharacter1, aCharacter2);

C ++角色战斗码问题

2 个答案: