. There are two kind of header files Class1 and Class2 h, h, two header file defined in the class pointer reference with each other, so can't use # include to refer to the other class definition

//Class1. H content is as follows:

The class CClass2;

The class CClass1
{
Public:
The class CInnerClass
{
};

Public:
CClass2 * pClass2=nullptr;//defined here right
};

//Class2. H content is as follows:

The class CClass1;

The class CClass2
{
Public:
CClass1 * pClass1=nullptr;//defined here right
CClass1: : CInnerClass * pInnerClass=nullptr;//error defined here, unable to compile
};

Thus cause cannot be defined in the CClass2 CClass1: : CInnerClass class pointer object, don't know if you have a solution?

CodePudding user response:

Class2. H forgetting contains class1. H header file? You lead statement defines the class1, but is not defined in class1 members, members of the directly defined in class2 class1 for private members, is a must see to it,

CodePudding user response:

Can, as long as the build CClass2 instances in the source file # include "class1. H" can, if not yet, change the compiler ~ ~ ~

CodePudding user response:

Are just in the source file contains the definition, also written in the source file

CodePudding user response:

Generally this kind of operation is to use a virtual class as, two classes are common and include this virtual class inheritance

CodePudding user response:

Header file contains 1 2 good, 1 does not contain 2, front under the class declaration class2, CPP file contains 2 header files

CodePudding user response:

To add a
The class CClass1: : CInnerClass;
Forward declaration is not line? Anyway, you this is a pointer,

CodePudding user response:

The first is because contain each other, so can't use the include,
I consider it a class CClass1: : CInnerClass; But this compilation will be wrong

CodePudding user response:

I use on VS2015, is your code, normal use,
Class1

 
# pragma once 

The class CClass2; 

The class CClass1 
{
Public: 
CClass1 () {printf (" CClass1 Constructor \ n "); } 
~ CClass1 () {printf (" CClass1 Destructor \ n "); } 
Public: 
The class CInnerClass 
{
Public: 
CInnerClass () {printf (" CInnerClass Constructor \ n "); } 
~ CInnerClass () {printf (" CInnerClass Destructor \ n "); } 
}; 

Public: 
CClass2 * pClass2=nullptr;//defined here right 
}; 

Class2

 
# pragma once 

# include "Class1. H" 
//Class2. H content is as follows: 

The class CClass1; 

The class CClass2 
{
Public: 
CClass2 () {printf (" CClass2 Constructor \ n "); } 
~ CClass2 () {printf (" CClass2 Destructor \ n "); } 
Public: 
CClass1 * pClass1=nullptr; 
CClass1: : CInnerClass * pInnerClass=nullptr; 
}; 

The main

 
#include  
# include "Class1. H" 
# include "Class2. H" 

Int main () 
{
CClass1 class1. 
CClass2 class2; 
return 0; 
} 

CodePudding user response:

Not to say that, in front of the two. H do not quote # include each other, in establishing CClass2 instances in the source file # include "class1. H" can (of course also should quote class2. H)

CodePudding user response:

Why not template, a header file write definition, can only define is CPP?

CodePudding user response:

According to zjq9931 reply, I found that, in accordance with the original approach, indeed can be compiled through, so it should be two classes have inner classes, will appear this problem, the problem is, indeed, I have written in the application of problem, because the program is more complex, now there are many types of class definition, so there is this kind of phenomenon, a temporary solution, encounter this kind of situation can only cancel the class definition in the class, but the program structure doesn't look perfect) :

The following is to modify the class definition

//Class1. H content is as follows:

The class CClass2;
The class CClass2: : CClass2InnerClass;//compile by

The class CClass1
{
Public:
CClass1 ()
{
}
~ CClass1 ()
{
}

Public:
The class CClass1InnerClass
{
Public:
Long aaa=10;
};

Public:
CClass2 * pClass2=nullptr;//defined here right
CClass2: : CClass2InnerClass * pClass2Inner=nullptr;
};


//Class2. H content is as follows:

The class CClass1;
The class CClass1: : CClass1InnerClass;//this cannot compile

The class CClass2
{
Public:
The class CClass2InnerClass
{
Public:
Long aaa=5;
};

Public:
CClass2 ()
{
}
~ CClass2 ()
{
}
Public:
CClass1 * pClass1=nullptr;
CClass1: : CClass1InnerClass * pInnerClass=nullptr;
};

Thus a reference each other class in the class, a can define internal class pointer object, don't know if you have a solution?

CodePudding user response:

Why do you so shaft ~ ~ ~

//Class1. H content is as follows:

The class CClass2;

The class CClass1
{
Public:
The class CInnerClass
{
};

Public:
CClass2 * pClass2=nullptr;//defined here right
};


//Class2. H content is as follows:

The class CClass1;

The class CClass2
{
Public:
CClass1 * pClass1=nullptr;//defined here right
CClass1: : CInnerClass * pInnerClass=nullptr;//here also normal
};

The test program:
#include
# include "class1. H"
# include "class2. H"

Int main ()
{
CClass2 c2.
Printf (" % p \ n ", c2. PInnerClass=0).

return 0;
}

CodePudding user response:

I use visual studio 2019 tested, if the parties have each other in the class and class in class pointer object, is not the first # include the above reference each other, then the actual CClass1 class1.
CClass2 class2;

CodePudding user response:

null