Can inner classes access private variables

Question

class Outer        class Inner       public          Inner              void func             private      static const char  const MYCONST      int var      void Outer  Inner  func         var   1     const char  const Outer  MYCONST    myconst     This errors out when I compile with class Outer  Inner  has no member named  var

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Anything that is part of Outer should have access to all of Outer s members  public or private   Edit  your compiler is correct  var is not a member of Inner   But if you have a reference or pointer to an instance of Outer  it could access that

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An inner class has access to all members of the outer class  but it does not have an implicit reference to a parent class instance  unlike some weirdness with Java   So if you pass a reference to the outer class to the inner class  it can reference anything in the outer class instance

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An inner class is a friend of the class it is defined within  So  yes  an object of type Outer  Inner can access the member variable var of an object of type Outer   Unlike Java though  there is no correlation between an object of type Outer  Inner and an object of the parent class  You have to make the parent child relationship manually    include  lt string gt   include  lt iostream gt   class Outer       class Inner               public              Inner Outer amp  x   parent x                 void func                                 std  string a    myconst1                   std  cout  lt  lt  parent var  lt  lt  std  endl                   if  a    MYCONST                      std  cout  lt  lt   string same   lt  lt  std  endl                                    else                     std  cout  lt  lt   string not same   lt  lt  std  endl                                          private              Outer amp   parent              public          Outer                i  this               var 4                     Outer Outer amp  other               i other               var 22                     void func                         i func                  private          static const char  const MYCONST          Inner i          int var      const char  const Outer  MYCONST    myconst    int main          Outer           o1      Outer           o2 o1       o1 func        o2 func

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var is not a member of inner class   To access var  a pointer or reference to an outer class instance should be used  e g  pOuter- var will work if the inner class is a friend of outer  or  var is public  if one follows C   standard strictly   Some compilers treat inner classes as the friend of the outer  but some may not  See this document for IBM compiler    A nested class is declared within the scope of another class  The name of a nested class is local to its enclosing class  Unless you use explicit pointers  references  or object names  declarations in a nested class can only use visible constructs  including type names  static members  and enumerators from the enclosing class and global variables   Member functions of a nested class follow regular access rules and have no special access privileges to members of their enclosing classes  Member functions of the enclosing class have no special access to members of a nested class

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An inner class is a friend of the class it is defined within  So  yes  an object of type Outer  Inner can access the member variable var of an object of type Outer   Unlike Java though  there is no correlation between an object of type Outer  Inner and an object of the parent class  You have to make the parent child relationship manually    include  lt string gt   include  lt iostream gt   class Outer       class Inner               public              Inner Outer amp  x   parent x                 void func                                 std  string a    myconst1                   std  cout  lt  lt  parent var  lt  lt  std  endl                   if  a    MYCONST                      std  cout  lt  lt   string same   lt  lt  std  endl                                    else                     std  cout  lt  lt   string not same   lt  lt  std  endl                                          private              Outer amp   parent              public          Outer                i  this               var 4                     Outer Outer amp  other               i other               var 22                     void func                         i func                  private          static const char  const MYCONST          Inner i          int var      const char  const Outer  MYCONST    myconst    int main          Outer           o1      Outer           o2 o1       o1 func        o2 func

User · Answer

Anything that is part of Outer should have access to all of Outer s members  public or private   Edit  your compiler is correct  var is not a member of Inner   But if you have a reference or pointer to an instance of Outer  it could access that

User · Answer

An inner class has access to all members of the outer class  but it does not have an implicit reference to a parent class instance  unlike some weirdness with Java   So if you pass a reference to the outer class to the inner class  it can reference anything in the outer class instance

User · Answer

An inner class has access to all members of the outer class  but it does not have an implicit reference to a parent class instance  unlike some weirdness with Java   So if you pass a reference to the outer class to the inner class  it can reference anything in the outer class instance

User · Answer

First of all  you are trying to access non-static member var outside the class which is not allowed in C     Mark s answer is correct      Anything that is part of Outer should have access to all of Outer s members  public or private    So you can do two things  either declare var as static or use a reference of an instance of the outer class to access  var   because a friend class or function also needs reference to access private data    Static var  Change var to static If you don t want var to be associated with the instances of the class    include  lt iostream gt   class Outer    private      static const char  const MYCONST      static int var   public     class Inner       public          Inner               Outer  var   1                    void func                int Outer  var   0   void Outer  Inner  func         std  cout  lt  lt   var    lt  lt  Outer  var     int main       Outer outer    Outer  Inner inner    inner func         Output- var  1  Non-static var  An object s reference is must access any non-static member variables     include  lt iostream gt   class Outer    private      static const char  const MYCONST      int var   public     class Inner       public          Inner Outer  amp outer              outer var   1                    void func const Outer  amp outer               void Outer  Inner  func const Outer  amp outer        std  cout  lt  lt   var    lt  lt  outer var     int main       Outer outer    Outer  Inner inner outer     inner func outer        Output- var  1  Edit - External links are links to my Blog

User · Answer

An inner class has access to all members of the outer class  but it does not have an implicit reference to a parent class instance  unlike some weirdness with Java   So if you pass a reference to the outer class to the inner class  it can reference anything in the outer class instance

User · Answer

var is not a member of inner class   To access var  a pointer or reference to an outer class instance should be used  e g  pOuter- var will work if the inner class is a friend of outer  or  var is public  if one follows C   standard strictly   Some compilers treat inner classes as the friend of the outer  but some may not  See this document for IBM compiler    A nested class is declared within the scope of another class  The name of a nested class is local to its enclosing class  Unless you use explicit pointers  references  or object names  declarations in a nested class can only use visible constructs  including type names  static members  and enumerators from the enclosing class and global variables   Member functions of a nested class follow regular access rules and have no special access privileges to members of their enclosing classes  Member functions of the enclosing class have no special access to members of a nested class

User · Answer

Anything that is part of Outer should have access to all of Outer s members  public or private   Edit  your compiler is correct  var is not a member of Inner   But if you have a reference or pointer to an instance of Outer  it could access that

User · Answer

First of all  you are trying to access non-static member var outside the class which is not allowed in C     Mark s answer is correct      Anything that is part of Outer should have access to all of Outer s members  public or private    So you can do two things  either declare var as static or use a reference of an instance of the outer class to access  var   because a friend class or function also needs reference to access private data    Static var  Change var to static If you don t want var to be associated with the instances of the class    include  lt iostream gt   class Outer    private      static const char  const MYCONST      static int var   public     class Inner       public          Inner               Outer  var   1                    void func                int Outer  var   0   void Outer  Inner  func         std  cout  lt  lt   var    lt  lt  Outer  var     int main       Outer outer    Outer  Inner inner    inner func         Output- var  1  Non-static var  An object s reference is must access any non-static member variables     include  lt iostream gt   class Outer    private      static const char  const MYCONST      int var   public     class Inner       public          Inner Outer  amp outer              outer var   1                    void func const Outer  amp outer               void Outer  Inner  func const Outer  amp outer        std  cout  lt  lt   var    lt  lt  outer var     int main       Outer outer    Outer  Inner inner outer     inner func outer        Output- var  1  Edit - External links are links to my Blog

User · Answer

An inner class is a friend of the class it is defined within  So  yes  an object of type Outer  Inner can access the member variable var of an object of type Outer   Unlike Java though  there is no correlation between an object of type Outer  Inner and an object of the parent class  You have to make the parent child relationship manually    include  lt string gt   include  lt iostream gt   class Outer       class Inner               public              Inner Outer amp  x   parent x                 void func                                 std  string a    myconst1                   std  cout  lt  lt  parent var  lt  lt  std  endl                   if  a    MYCONST                      std  cout  lt  lt   string same   lt  lt  std  endl                                    else                     std  cout  lt  lt   string not same   lt  lt  std  endl                                          private              Outer amp   parent              public          Outer                i  this               var 4                     Outer Outer amp  other               i other               var 22                     void func                         i func                  private          static const char  const MYCONST          Inner i          int var      const char  const Outer  MYCONST    myconst    int main          Outer           o1      Outer           o2 o1       o1 func        o2 func

User · Answer

Anything that is part of Outer should have access to all of Outer s members  public or private   Edit  your compiler is correct  var is not a member of Inner   But if you have a reference or pointer to an instance of Outer  it could access that

User · Answer

An inner class is a friend of the class it is defined within  So  yes  an object of type Outer  Inner can access the member variable var of an object of type Outer   Unlike Java though  there is no correlation between an object of type Outer  Inner and an object of the parent class  You have to make the parent child relationship manually    include  lt string gt   include  lt iostream gt   class Outer       class Inner               public              Inner Outer amp  x   parent x                 void func                                 std  string a    myconst1                   std  cout  lt  lt  parent var  lt  lt  std  endl                   if  a    MYCONST                      std  cout  lt  lt   string same   lt  lt  std  endl                                    else                     std  cout  lt  lt   string not same   lt  lt  std  endl                                          private              Outer amp   parent              public          Outer                i  this               var 4                     Outer Outer amp  other               i other               var 22                     void func                         i func                  private          static const char  const MYCONST          Inner i          int var      const char  const Outer  MYCONST    myconst    int main          Outer           o1      Outer           o2 o1       o1 func        o2 func

[c++] Can inner classes access private variables?

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