好的，我是HTML / Javascript / PHP专业人士，但我正在努力学习C ++。我还是新手，我有一个C ++编程项目，我有错误。
包含int main（）的文件是'football.cpp'，我有三个必须使用的类的.h和.cpp文件：Game，Team和Date。 Team的每个实例都包含一个Games游戏，每个游戏都包含一个Date。日期不包含任何其他类的实例。
我试图找到一种在文件顶部使用#include和#ifndef语句的方法，这样我在编译时就不会出错，但我还没有找到一个有效的组合。我不确定是否还有其他错误。这是我目前的#include部分，不包括其他库：
football.cpp
#include "game.h"
#include "team.h"
#include "date.h"
team.h
#ifndef __game_h_
#define __game_h_
#endif
team.cpp
#include "team.h"
#ifndef __game_h_
#define __game_h_
#endif
game.h
#ifndef __date_h_
#define __date_h_
#endif
game.cpp
#include "game.h"
#ifndef __date_h_
#define __date_h_
#endif
date.cpp
#include "date.h"
我使用Cygwin g ++编译器，我用来编译它的行是：
g++ football.cpp team.cpp game.cpp date.cpp -o football.exe
以下是我得到的所有错误:(警告，文字墙）
$ g++ football.cpp team.cpp game.cpp date.cpp -o football.exe
In file included from football.cpp:9:0:
game.h:15:96: error: ‘Date’ has not been declared
game.h:24:1: error: ‘Date’ does not name a type
game.h:37:1: error: ‘Date’ does not name a type
football.cpp: In function ‘int main(int, char*)’:
football.cpp:65:70: error: no matching function for call to ‘Game::Game(std::string&, std::string&, int [5], int [5], Date&)’
game.h:15:1: note: candidates are: Game::Game(std::string, std::string, const int, const int*, int)
game.h:14:1: note: Game::Game()
game.h:10:12: note: Game::Game(const Game&)
In file included from team.cpp:4:0:
team.h:24:8: error: ‘Game’ was not declared in this scope
team.h:24:12: error: template argument 1 is invalid
team.h:24:12: error: template argument 2 is invalid
team.cpp: In member function ‘float Team::getStat3()’:
team.cpp:36:26: error: request for member ‘size’ in ‘((Team*)this)->Team::games’, which is of non-class type ‘int’
team.cpp:37:21: error: invalid types ‘int[int]’ for array subscript
team.cpp:37:50: error: invalid types ‘int[int]’ for array subscript
team.cpp:38:21: error: invalid types ‘int[int]’ for array subscript
team.cpp:38:47: error: invalid types ‘int[int]’ for array subscript
team.cpp:38:76: error: invalid types ‘int[int]’ for array subscript
team.cpp:38:106: error: invalid types ‘int[int]’ for array subscript
team.cpp: In function ‘bool compare2(Team, Team)’:
team.cpp:45:39: error: request for member ‘size’ in ‘t1.Team::games’, which is of non-class type ‘const int’
team.cpp:46:39: error: request for member ‘size’ in ‘t2.Team::games’, which is of non-class type ‘const int’
team.cpp:50:17: error: request for member ‘size’ in ‘t1.Team::games’, which is of non-class type ‘const int’
team.cpp:50:35: error: request for member ‘size’ in ‘t2.Team::games’, which is of non-class type ‘const int’
team.cpp:52:24: error: request for member ‘size’ in ‘t1.Team::games’, which is of non-class type ‘const int’
team.cpp:52:43: error: request for member ‘size’ in ‘t2.Team::games’, which is of non-class type ‘const int’
team.cpp: In function ‘bool compare3(Team, Team)’:
team.cpp:62:29: error: passing ‘const Team’ as ‘this’ argument of ‘float Team::getStat3()’ discards qualifiers
team.cpp:63:29: error: passing ‘const Team’ as ‘this’ argument of ‘float Team::getStat3()’ discards qualifiers
In file included from game.cpp:5:0:
game.h:15:96: error: ‘Date’ has not been declared
game.h:24:1: error: ‘Date’ does not name a type
game.h:37:1: error: ‘Date’ does not name a type
game.cpp: In constructor ‘Game::Game()’:
game.cpp:26:3: error: ‘date’ was not declared in this scope
game.cpp:26:15: error: ‘Date’ was not declared in this scope
game.cpp: At global scope:
game.cpp:29:94: error: ‘Date’ has not been declared
game.cpp:29:1: error: prototype for ‘Game::Game(std::string, std::string, int*, int*, int)’ does not match any in class ‘Game’
game.h:10:12: error: candidates are: Game::Game(const Game&)
game.h:15:1: error: Game::Game(std::string, std::string, const int*, const int*, int)
game.cpp:13:1: error: Game::Game()
game.cpp: In member function ‘int Game::getVisitingScore(int) const’:
game.cpp:80:10: error: ‘visitingScores’ was not declared in this scope
game.cpp: At global scope:
game.cpp:94:1: error: ‘Date’ does not name a type
如果需要进一步澄清，将编辑，但我认为不会。
非常感谢任何帮助。
答案 0 :(得分：5)
我认为您误解了使用包含警卫。
#ifndef __game_h_
#define __game_h_
// ...
#endif
上述语句集通常仅用于描述游戏界面的头文件中，以防止多次包含该头文件。
但是在你的代码中，你已经在标题和实现中添加了包含保护，而且你似乎也混淆了实体 - 除非我误解了你的文件内容 - 例如在中team.h ，你有似乎包含游戏的守卫。
我的猜测是你滥用包含警卫实际上是在阻止某些类型被定义。
正如其他人所提到的，不要使用以双下划线开头的名称。
例如，在团队标头中添加包含警戒以防止多次包含该文件，并为包含警卫提供反映他们正在守护的模块的名称：
// team.h
#ifndef TEAM_H
#define TEAM_H
// ... code for team.h in here
#endif // TEAM_H
答案 1 :(得分：1)
看起来你有两个问题：第一个是你在源文件中使用包含警戒;第二个是你包含文件的顺序是错误的。
首先，包括警卫。其他人已经回答了这个问题，所以我会简短一些。包含保护仅在头文件中使用，以防止多次声明类/类型。例如，如果我有：
<强> “game.h”：
class Game {};
<强> “game.cpp”：
#include "game.h"
#include "game.h" // ERROR: class Game is declared twice.
要解决这个问题，我会在“game.h”中使用包含警戒：
#ifndef GAME_H_INCLUDED
#define GAME_H_INCLUDED
class Game {};
#endif
第一次包含文件时，未定义GAME_H_INCLUDED，因此声明了Game。第二次包含，GAME_H_INCLUDED 是定义的，因此会跳过声明。
您遇到的问题是您的源文件中的包含保护将导致跳过所有实现：
破解“game.cpp”：
#include "game.h"
#ifndef GAME_H_INCLUDED // This is defined in "game.h" so everything will be
// skipped until #endif is encountered.
#define GAME_H_INCLUDED
// Implementation of Game class
#endif
其次，包含标题的顺序不正确。我猜你有这样的事情：
<强> “game.h”
#ifndef GAME
#define GAME
class Game
{
Date mDate; // Member of type Date, declared in "date.h"
};
#endif
<强> “date.h”
#ifndef GAME
#define GAME
class Date
{
};
#endif
<强> “game.cpp”
#include "game.h" // ERROR: Game relies on the Date class,
// which isn't included yet
#include "date.h"
要解决此问题，请在“game.cpp”中交换包含的顺序：
<强> “game.cpp”
#include "date.h"
#include "game.h" // Fine, we know what a Date is now.
或在“game.h”中加入“date.h”：
<强> “game.h”
#include "date.h"
#ifndef GAME
#define GAME
class Game
{
Date mDate; // Member of type Date, declared in "date.h"
};
#endif
<强> “game.cpp”
#include "game.h" // Still fine, "date.h" is included by "game.h"
答案 2 :(得分：0)
你不需要c ++文件中的警卫
答案 3 :(得分：0)
错误是您应该只在头文件中使用包含保护
如果你有
BaseClass.h
struct HumanEntity { }
然后有不同的类使用该基类，没有包含保护可能会遇到问题。这就是你放
的原因#ifndef __MYGUARD
#define __MYGUARD
... // here is your header code
#endif