头文件中的 class 给出了许多错误
A class in header file giving many errors
我想制作一个 class 库，以便我可以在我的代码中使用它。这就是为什么我将我的 class 分成 2 个文件 - s_int.h 和 s_int.cpp 但是编译给出了太多与 class 相关的错误。通常我会看到一些 'anonymous aggregate' 与构造函数和析构函数相关的错误。这是我的代码：
main.cpp :
#include "s_int.h"
#include <iostream>
#include <string>
using namespace std;
int main()
{
s_int integer;
integer = "11111111111111111111111111111111111";
s_int integer1(integer);
cout << integer.integer << "\n";
cout << integer1.integer << "\n";
}
s_int.cpp
#include <bits/stdc++.h>
#include "s_int.h"
using namespace std;
s_int::s_int(std::string inp)
{
this-> integer = inp;
}
s_int::s_int(const s_int &inp)
{
this-> integer = inp.integer;
}
void s_int::operator = (const string &inp )
{
integer = inp;
}
void s_int::operator = (const s_int &inp )
{
integer = inp.integer;
}
s_int.h
#include <bits/stdc++.h>
#ifndef s_int
#define s_int
using namespace std;
class s_int
{
public:
string integer = "";
s_int(std::string inp = "") ;
s_int(const s_int &inp) ;
void operator = (const string &inp );
void operator = (const s_int &inp );
};
#endif
编译错误（以备不时之需）
$ g++ main.cpp s_int.h s_int.cpp
main.cpp: In function ‘int main()’:
main.cpp:7:11: error: ‘integer’ was not declared in this scope
7 | s_int integer;
| ^~~~~~~
main.cpp:9:11: error: ‘integer1’ was not declared in this scope
9 | s_int integer1(integer);
| ^~~~~~~~
s_int.h:9:26: error: expected ‘)’ before ‘inp’
9 | s_int(std::string inp = "") ;
| ~ ^~~~
| )
s_int.h:10:15: error: expected unqualified-id before ‘const’
10 | s_int(const s_int &inp) ;
| ^~~~~
s_int.h:10:15: error: expected ‘)’ before ‘const’
10 | s_int(const s_int &inp) ;
| ~^~~~~
| )
s_int.h:13:33: error: ‘inp’ has not been declared
13 | s_int operator + (s_int inp );
| ^~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with constructor not allowed in anonymous aggregate
8 | string integer = "";
| ^~~~~~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with destructor not allowed in anonymous aggregate
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with copy assignment operator not allowed in anonymous aggregate
s_int.h:14:2: error: abstract declarator ‘<unnamed class>’ used as declaration
14 | };
| ^
In file included from s_int.cpp:2:
s_int.h:9:26: error: expected ‘)’ before ‘inp’
9 | s_int(std::string inp = "") ;
| ~ ^~~~
| )
s_int.h:10:15: error: expected unqualified-id before ‘const’
10 | s_int(const s_int &inp) ;
| ^~~~~
s_int.h:10:15: error: expected ‘)’ before ‘const’
10 | s_int(const s_int &inp) ;
| ~^~~~~
| )
s_int.h:13:33: error: ‘inp’ has not been declared
13 | s_int operator + (s_int inp );
| ^~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with constructor not allowed in anonymous aggregate
8 | string integer = "";
| ^~~~~~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with destructor not allowed in anonymous aggregate
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with copy assignment operator not allowed in anonymous aggregate
s_int.h:14:2: error: abstract declarator ‘<unnamed class>’ used as declaration
14 | };
| ^
s_int.cpp:5:17: error: expected id-expression before ‘(’ token
5 | s_int::s_int(std::string inp)
| ^
s_int.cpp:9:17: error: expected id-expression before ‘(’ token
9 | s_int::s_int(const s_int &inp)
| ^
s_int.cpp:13:47: error: ‘void operator=(const string&)’ should have been declared inside ‘::’
13 | void s_int::operator = (const string &inp )
| ^
s_int.cpp:13:15: error: ‘void operator=(const string&)’ must be a nonstatic member function
13 | void s_int::operator = (const string &inp )
| ^~
s_int.cpp:17:46: error: ‘void operator=(const int&)’ should have been declared inside ‘::’
17 | void s_int::operator = (const s_int &inp )
| ^
s_int.cpp:17:15: error: ‘void operator=(const int&)’ must be a nonstatic member function
17 | void s_int::operator = (const s_int &inp )
| ^~
s_int.cpp:21:29: error: expected constructor, destructor, or type conversion before ‘(’ token
21 | s_int s_int::operator + (s_int inp )
| ^
#define s_int
会让编译器将 class 名称 s_int 替换为空字符串，这会导致麻烦。
使用另一个名称来定义包含防护。
正在使用
#pragma once
如果您的环境支持此功能，也很好。
您还必须将 #include "s_int.h" 添加到 main.cpp，正如@NathanOliver 所说。
你有没有想过把#include "s_int.h" 放在主 class 中？
Macros are very simple text substitution。凡是找到宏标识符的地方，无论这样做是否有意义，标识符都会被标识符后面的任何内容替换。所以当你
#ifndef s_int
代码中任何有 s_int 的地方，它都被替换为空。也就是说
s_int integer;
变成
integer;
编译器不知道如何处理它。
class s_int
变成
class
进行未命名的 class 定义。如果您尝试使用 now-nameless class.
就会出现混乱
您需要确保谨慎使用宏。因此，许多编码约定要求宏全部为大写，以使其脱颖而出。
在 Include Guard 的情况下，守卫必须是完全唯一的。如果您在代码中重复使用该标识符，就会出现您在此代码中看到的那种意想不到的文本替换。如果你有多个 headers 由相同的标识符保护，第一次使用保护将阻止所有其他 headers 也使用它。这是一个非常糟糕的场景。
可以通过
缓解
#pragma once
如果您的编译器支持 once，大多数主要编译器都支持 once，但如果不支持 #pragmas are allowed to be silently discarded, so you may not even know your headers aren't protected. In addition, sufficiently complicated project structures can fool once
我对你的代码做了一些改动。
我删除了不需要的不必要的引用，例如 = 运算符的重载，我们不需要因为我们不打算更改给定的参数。
我们不需要初始化 string integer;当我们为它实现构造函数时。
您还应该考虑，我们如何定义宏 #ifndef 和 #define 在头文件中。
结合你的头文件和它的方法实现。
s_int.h
#include <bits/stdc++.h>
#ifndef S_INT_H
#define S_INT_H
using namespace std;
class s_int
{
public:
string integer;
s_int(std::string inp = "")
{
this->integer = inp;
}
s_int(const s_int *inp)
{
integer = inp->integer;
}
void operator=(const string inp)
{
this->integer = inp;
}
void operator= (const s_int inp)
{
this->integer = inp.integer;
}
};
#endif
main.cpp
#include "s_int.h"
#include <iostream>
#include <string>
using namespace std;
int main()
{
s_int integer;
integer = "11111111111111111111111111111111111";
s_int integer1(integer);
cout << integer.integer << "\n";
cout << integer1.integer << "\n";
}
希望对你有所帮助，你想用正确的方式在cpp中写类。
我想制作一个 class 库，以便我可以在我的代码中使用它。这就是为什么我将我的 class 分成 2 个文件 - s_int.h 和 s_int.cpp 但是编译给出了太多与 class 相关的错误。通常我会看到一些 'anonymous aggregate' 与构造函数和析构函数相关的错误。这是我的代码：
main.cpp :
#include "s_int.h"
#include <iostream>
#include <string>
using namespace std;
int main()
{
s_int integer;
integer = "11111111111111111111111111111111111";
s_int integer1(integer);
cout << integer.integer << "\n";
cout << integer1.integer << "\n";
}
s_int.cpp
#include <bits/stdc++.h>
#include "s_int.h"
using namespace std;
s_int::s_int(std::string inp)
{
this-> integer = inp;
}
s_int::s_int(const s_int &inp)
{
this-> integer = inp.integer;
}
void s_int::operator = (const string &inp )
{
integer = inp;
}
void s_int::operator = (const s_int &inp )
{
integer = inp.integer;
}
s_int.h
#include <bits/stdc++.h>
#ifndef s_int
#define s_int
using namespace std;
class s_int
{
public:
string integer = "";
s_int(std::string inp = "") ;
s_int(const s_int &inp) ;
void operator = (const string &inp );
void operator = (const s_int &inp );
};
#endif
编译错误（以备不时之需）
$ g++ main.cpp s_int.h s_int.cpp
main.cpp: In function ‘int main()’:
main.cpp:7:11: error: ‘integer’ was not declared in this scope
7 | s_int integer;
| ^~~~~~~
main.cpp:9:11: error: ‘integer1’ was not declared in this scope
9 | s_int integer1(integer);
| ^~~~~~~~
s_int.h:9:26: error: expected ‘)’ before ‘inp’
9 | s_int(std::string inp = "") ;
| ~ ^~~~
| )
s_int.h:10:15: error: expected unqualified-id before ‘const’
10 | s_int(const s_int &inp) ;
| ^~~~~
s_int.h:10:15: error: expected ‘)’ before ‘const’
10 | s_int(const s_int &inp) ;
| ~^~~~~
| )
s_int.h:13:33: error: ‘inp’ has not been declared
13 | s_int operator + (s_int inp );
| ^~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with constructor not allowed in anonymous aggregate
8 | string integer = "";
| ^~~~~~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with destructor not allowed in anonymous aggregate
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with copy assignment operator not allowed in anonymous aggregate
s_int.h:14:2: error: abstract declarator ‘<unnamed class>’ used as declaration
14 | };
| ^
In file included from s_int.cpp:2:
s_int.h:9:26: error: expected ‘)’ before ‘inp’
9 | s_int(std::string inp = "") ;
| ~ ^~~~
| )
s_int.h:10:15: error: expected unqualified-id before ‘const’
10 | s_int(const s_int &inp) ;
| ^~~~~
s_int.h:10:15: error: expected ‘)’ before ‘const’
10 | s_int(const s_int &inp) ;
| ~^~~~~
| )
s_int.h:13:33: error: ‘inp’ has not been declared
13 | s_int operator + (s_int inp );
| ^~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with constructor not allowed in anonymous aggregate
8 | string integer = "";
| ^~~~~~~
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with destructor not allowed in anonymous aggregate
s_int.h:8:16: error: member ‘std::string <unnamed class>::integer’ with copy assignment operator not allowed in anonymous aggregate
s_int.h:14:2: error: abstract declarator ‘<unnamed class>’ used as declaration
14 | };
| ^
s_int.cpp:5:17: error: expected id-expression before ‘(’ token
5 | s_int::s_int(std::string inp)
| ^
s_int.cpp:9:17: error: expected id-expression before ‘(’ token
9 | s_int::s_int(const s_int &inp)
| ^
s_int.cpp:13:47: error: ‘void operator=(const string&)’ should have been declared inside ‘::’
13 | void s_int::operator = (const string &inp )
| ^
s_int.cpp:13:15: error: ‘void operator=(const string&)’ must be a nonstatic member function
13 | void s_int::operator = (const string &inp )
| ^~
s_int.cpp:17:46: error: ‘void operator=(const int&)’ should have been declared inside ‘::’
17 | void s_int::operator = (const s_int &inp )
| ^
s_int.cpp:17:15: error: ‘void operator=(const int&)’ must be a nonstatic member function
17 | void s_int::operator = (const s_int &inp )
| ^~
s_int.cpp:21:29: error: expected constructor, destructor, or type conversion before ‘(’ token
21 | s_int s_int::operator + (s_int inp )
| ^
#define s_int
会让编译器将 class 名称 s_int 替换为空字符串，这会导致麻烦。
使用另一个名称来定义包含防护。
正在使用
#pragma once
如果您的环境支持此功能，也很好。
您还必须将 #include "s_int.h" 添加到 main.cpp，正如@NathanOliver 所说。
你有没有想过把#include "s_int.h" 放在主 class 中？
Macros are very simple text substitution。凡是找到宏标识符的地方，无论这样做是否有意义，标识符都会被标识符后面的任何内容替换。所以当你
#ifndef s_int
代码中任何有 s_int 的地方，它都被替换为空。也就是说
s_int integer;
变成
integer;
编译器不知道如何处理它。
class s_int
变成
class
进行未命名的 class 定义。如果您尝试使用 now-nameless class.
就会出现混乱您需要确保谨慎使用宏。因此，许多编码约定要求宏全部为大写，以使其脱颖而出。
在 Include Guard 的情况下，守卫必须是完全唯一的。如果您在代码中重复使用该标识符，就会出现您在此代码中看到的那种意想不到的文本替换。如果你有多个 headers 由相同的标识符保护，第一次使用保护将阻止所有其他 headers 也使用它。这是一个非常糟糕的场景。
可以通过
缓解#pragma once
如果您的编译器支持 once，大多数主要编译器都支持 once，但如果不支持 #pragmas are allowed to be silently discarded, so you may not even know your headers aren't protected. In addition, sufficiently complicated project structures can fool once
我对你的代码做了一些改动。
我删除了不需要的不必要的引用，例如 = 运算符的重载，我们不需要因为我们不打算更改给定的参数。
我们不需要初始化 string integer;当我们为它实现构造函数时。
您还应该考虑，我们如何定义宏 #ifndef 和 #define 在头文件中。
结合你的头文件和它的方法实现。
s_int.h
#include <bits/stdc++.h>
#ifndef S_INT_H
#define S_INT_H
using namespace std;
class s_int
{
public:
string integer;
s_int(std::string inp = "")
{
this->integer = inp;
}
s_int(const s_int *inp)
{
integer = inp->integer;
}
void operator=(const string inp)
{
this->integer = inp;
}
void operator= (const s_int inp)
{
this->integer = inp.integer;
}
};
#endif
main.cpp
#include "s_int.h"
#include <iostream>
#include <string>
using namespace std;
int main()
{
s_int integer;
integer = "11111111111111111111111111111111111";
s_int integer1(integer);
cout << integer.integer << "\n";
cout << integer1.integer << "\n";
}
希望对你有所帮助，你想用正确的方式在cpp中写类。