Implementation of callback functions (pointer to a class member function)

See C and C ++CodeChunk Allison

 

Menu implementation

# Include <iostream> Using   Namespace  STD;  Class  Object {  Public  :  Void Retrieve () {cout < "  Object: retrieve \ n  "  ;}  Void Insert () {cout <"  Object: insert \ n  "  ;}  Void Update () {cout < "  Object: Update \ n  "  ;}  Void Process ( Int  Choice );  Private  :      Static   Void (Object: * farray [3  ]) () ;};  Void (Object: * object: farray [ 3 ]) () = { & Object: retrieve, & Object: insert, & Object: Update };  Void Object: Process ( Int  Choice ){  If ( 0 <= Choice & choice <=2  ){(  This -> * Farray [choice]) () ;}}  Int  Main (){  Int Show_menu ( Void  ); Object O;  For  (;;){  Int Choice = Show_menu (); cout < "  Choice = " <Choice < Endl;  If ( 1 <= Choice & choice <= 3  ) {O. Process (Choice - 1  );}  Else   If (Choice = 4  ){  Break  ;}} Return   0  ;}  Int Show_menu ( Void  ) {Cout < "  ======================== Menu ==============================  " < Endl; cout < "  1. Retrieve  " < Endl; cout <"  2. Insert  " < Endl; cout < "  3. Update  " < Endl; cout < "  4. Exit  " < Endl; cout < "  Please input Witch number you choose: "  ;  Char  Input; CIN > Input;  Return Input- '  0  '  ;} 

Running Effect

 

Use typedef to clear pointers to member functions

# Include <iostream> Using   Namespace  STD;  Class Object {  Public  :  Void Retrieve () {cout < "  Object: retrieve \ n  "  ;}  Void Insert () {cout < "  Object: insert \ n  "  ;}  Void Update () {cout < " Object: Update \ n  "  ;}  Void Process ( Int  Choice );  Private  : Typedef  Void (Object ::* OMF )();  Static OMF farray [ 3  ];  //  Static void (Object: * farray [3]) (); }; Object: OMF object: farray [  3 ] = //  Void (Object: * object: farray [3]) () =  { & Object: retrieve, & Object: insert, & Object: Update };  Void Object: Process ( Int  Choice ){  If ( 0 <= Choice & choice <=2  ){(  This -> * Farray [choice]) () ;}}  Int  Main (){  Int Show_menu ( Void  ); Object O;  For  (;;){  Int Choice = Show_menu (); cout < "  Choice = " <Choice < Endl;  If ( 1 <= Choice & choice <= 3  ) {O. Process (Choice - 1  );}  Else   If (Choice = 4  ){  Break  ;}} Return   0  ;}  Int Show_menu ( Void  ) {Cout < "  ======================== Menu ==============================  " < Endl; cout < "  1. Retrieve  " < Endl; cout <"  2. Insert  " < Endl; cout < "  3. Update  " < Endl; cout < "  4. Exit  " < Endl; cout < "  Please input Witch number you choose: "  ;  Char  Input; CIN > Input;  Return Input- '  0  '  ;}