我正在制作一个基于文本的基础RPG抱歉，如果我的问题是愚蠢的，因为我是c +的新手。所以基本上我有一个小型的战斗类，我必须从地图类来回链接，所以我不得不转发声明我的地图类，它会出现错误。顺便说一句，抱歉没有任何意见。
以下是错误：invalid use of incomplete type class Map
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
class Map;
class Player
{
public:
int health;
int damage;
int defense;
int gems=0;
string race;
string name;
string location;
};
class Enemy
{
public:
int ehealth;
int edamage;
int edefense;
int echoice;
};
class combat
{
public:
Map* mapobj;
int damagedealt;
Player playerobj;
Enemy enemeyobj;
string cchoice;
string retry;
void initial()
{
cout <<"A wild orc has appeared\n";
cout <<"What do you do?\n";
cout <<"---------------------------\n";
cout <<"|-------------------------|\n";
cout <<"|----Attack-----Defend----|\n";
cout <<"|-------------------------|\n";
cout <<"---------------------------\n";
cin >>cchoice;
this->battle();
}
void newturn()
{
cout <<"The orc is still alive!";
cout <<"What do you do?";
cout <<"\n---------------------------\n";
cout <<"|-------------------------|\n";
cout <<"|----Attack-----Defend----|\n";
cout <<"|-------------------------|\n";
cout <<"---------------------------\n";
cin >>cchoice;
this->battle();
};
void battle()
{
enemeyobj.echoice = rand() % 2;
if (enemeyobj.echoice= 1)
{
if (cchoice=="Attack")
{
playerobj.damage;
enemeyobj.ehealth=enemeyobj.ehealth-playerobj.damage;
cout <<"You did "<<playerobj.damage<<" points of damge to the enemey.\n";
if (enemeyobj.ehealth>0)
{
playerobj.health=enemeyobj.edamage-playerobj.health;
cout <<"The enemyattacked you. You now have "<<playerobj.health<<" health";
if (playerobj.health>0)
{
this->newturn();
}
else if (playerobj.health<=0)
{
cout <<playerobj.name<<"was killed\n";
cout <<"Game Over";
}
}
else if (enemeyobj.ehealth<=0)
{
cout <<"You have defeated the orc!";
if (playerobj.location=="a")
{
mapobj->relaypointa();
}
}
}
else if (cchoice=="Defend")
{
damagedealt=enemeyobj.edamage-playerobj.defense;
playerobj.health=damagedealt-playerobj.health;
cout <<"You defend but the enemey was able to deal\n";
cout <<damagedealt<<" points of damage your health is\n";
cout <<playerobj.health;
if (playerobj.health>0)
{
this->newturn();
}
else if (playerobj.health<=0)
{
cout <<playerobj.name<<"was killed\n";
cout <<"Game Over";
}
}
}
else if (enemeyobj.echoice=2)
{
if (cchoice=="Attack")
{
damagedealt=enemeyobj.edefense-playerobj.damage;
enemeyobj.ehealth=enemeyobj.ehealth-damagedealt;
cout <<"You did "<<damagedealt<<" points of damage to the enemey";
if (enemeyobj.ehealth>0)
{
this->newturn();
}
else if (enemeyobj.ehealth<=0)
{
cout <<"You have defeated the orc!";
mapobj->relaypointa();
}
}
else if (cchoice=="Defend")
{
cout <<"Both parties defended";
this->newturn();
}
}
}
};
class Map
{
public:
combat combatobj;
string mchoice;
int espawn;
Player playerobj;
Enemy enemeyobj;
void relaypointaespawn()
{
playerobj.location=="relaypointa";
enemeyobj.ehealth = rand() % 50 + 100;
enemeyobj.edamage = rand() % 50 + 75;
enemeyobj.edefense = rand() % 50 + 50;
combatobj.initial();
}
void relaypointa()
{
cout <<"You have found yourself at the\n";
cout <<"mouth of a mighty river to the north\n";
cout <<"What do you want to do?\n";
}
void relaypointb()
{
playerobj.location=="relaypointb";
cout << "\n\n%%%%%%%%%%%%%%%%%%%%\n";
cout << "% %\n";
cout << "% #Wild North# %\n";
cout << "% %\n";
cout << "%%%%%%%%%%%%%%%%%%%%\n\n";
cout <<"You have entered the wild north this is where your journey starts\n";
cout <<"What would you like to do\n\n";
cin >>mchoice;
if (mchoice=="Travel")
{
cout <<"Where would you like to travel?\n";
cin >>mchoice;
if (mchoice=="North")
{
}
else if (mchoice=="East")
{
}
else if (mchoice=="South")
{
}
else if (mchoice=="West")
{
this->relaypointaespawn();
}
else
{
cout <<"Invalid command\n\n";
this->relaypointb();
}
}
}
void relaypointcespawn()
{
playerobj.location=="a";
enemeyobj.ehealth = rand() % 50 + 100;
enemeyobj.edamage = rand() % 50 + 75;
enemeyobj.edefense = rand() % 50 + 50;
espawn = rand() % 2;
}
};
答案 0 :(得分：61)
Map的首次使用位于combat的函数内。这是在定义Map之前发生的，因此是错误。
前向声明只表示稍后将定义一个特定的类，因此可以引用它或指向对象等。但是前向声明并没有说明类具有哪些成员，因此就编译器而言我担心在完全宣布Map之前你不能使用任何一个。
解决方案是遵循.h文件中的类声明的C ++模式和.cpp中的函数体。这样，所有声明都出现在第一个定义之前，并且编译器知道它正在使用什么。
答案 1 :(得分：2)
我只是提供另一个案例，您可以收到此错误消息。解决方案与Adam上面提到的相同。这是来自真实的代码，我重命名了类名。
class FooReader {
public:
/** Constructor */
FooReader() : d(new FooReaderPrivate(this)) { } // will not compile here
.......
private:
FooReaderPrivate* d;
};
====== In a separate file =====
class FooReaderPrivate {
public:
FooReaderPrivate(FooReader*) : parent(p) { }
private:
FooReader* parent;
};
以上将不会通过编译器并获取错误：无效使用不完整类型FooReaderPrivate。您基本上必须将内联部分放入* .cpp实现文件中。还行吧。我在这里想说的是你可能有设计问题。在某些情况下，可能需要交叉引用两个类，但我认为最好在设计开始时避免使用它们。我错了，但请评论然后我会更新我的帖子。