1 C++ Bjarne Stroustrupp5 C++ C++ Qt p10 Trolltech WINDOWS Qt C++ p11 VC Wizard C++BCB C++ p17 STL Traits p19 C++ View C++ p25 Smart Pointer p27

Transcription

1 C++ Bjarne Stroustrup Traits BCB VCL

2 1 C++ Bjarne Stroustrupp5 C++ C++ Qt p10 Trolltech WINDOWS Qt C++ p11 VC Wizard C++BCB C++ p17 STL Traits p19 C++ View C++ p25 Smart Pointer p27 Smart pointer C++ C++ Report C/C++ Uesrs Journal C++ C++ C++ View C++ View C++ View BCB VCL p30 VCL 2

3 1 Visual C++JavaC# Visual C++ BBS Q C VC C++ A C++ C++ VC CC++VC Java BBS Q OO C++ Java AJava C++OO CC++VCJava C# BBS Q A CC++VCCOMJavaC# C C++VCBC Microsoft VC Java C++OO Sun Moon OO OO OO Java 3

4 1 Microsoft Copy&Paste OO OO C# & Java OO C++ View IT & C++ View C++ C/C++ C++ View MFC C++ View 4

5 1 myan C++ Bjarne Stroustrup Good Luck with your magazine Bjarne Stroustrup 1950 AT&T AT&T ACM Stroustrup B. S C with Class C ANSI/ISO C++ B. S The C++ Programming Language C++ B. S 20 C++ Internet JavaC# Script C++ C++ B. S Stroustrup FAQ C++ The C++ Programming Language, 1998 C++ C++ C++ C++ The Design and Evolution of C++ The C++ Programming Language Locales Standard-Library Exception Safety Stroustrup 5

6 1 C++ Pascal C++ Pascal C C++ C C++ C++ C C++ C++ C C C C++ OO Smalltalk Smalltaok Smalltalk C++ Smalltalk C++ C++ C++ C++ C++ C++ string s; // Standard C++ style cin >> s; char s[max]; /* Standard C style */ scanf("%s",s); C++ C++ C++ C++ B. S 6

7 1 C++ (cast) COBOL, C C++ ANSI/ISO C++ ISO C++ C++ C++ strings, lists, vectors, maps C++ C++ RTTI C++ N C C++C C++ C vector, list, map, string C Java? C++Java The Design and Evolution of C++C++ C++ SUN Java C++Java 7

8 1 Java Smalltalk Java Sun Java C++ Smalltalk Java C++Smalltalk Java Java Java 1.1 Java 1998 James GoslingJava Java W. Kahan How Java s Floating-Point Hurts Everyone Everywhere Java Java Java Java Java Sun Java Windows Windows/Intel Java/JVM JVM JVM Java VM/OS C++ Java is not platform-independent, it is the platform B. S C++ C++ Java C++ C# C# Ada C++ Ada 8

9 1 C++ The Design and Evolution of C++ C++ C++ C++ C++ C++ Z Z C++ C++ Z Z Z C++ C C++ C++ C C++ C++ C++ C 9

10 1 Qt Open Source C++ Linux KDE 1992 Qt 1994 Trolltech 1995 Qt Qt Qt 3.0 beta 1 Qt Designer Qt Linguist Open Source GNOME/Gtk Qt QPL Open Source for Unix/Linux Qt/Windows 30 Windows Trolltech Qt/Windows Non-Commercial License Qt Trolltech API GUI OpenGL Qt Microsoft Windows 95/98/NT/2000MacOS XLinux SolarisHP-UXTru64 (Digital UNIX)IrixFreeBSDBSD/OSSCO AIX Trolltech 10

11 1 Ian Joyner cber Ian Joyner C++?? A Critique of C++ and Programming and Language Trends of the 1990s 3/EIan Joyner 1996 Ian Joyner Ian Joyner ;-) Ian Joyner Objects Unencapsulated, Ian Joyner i.joyner@acm.org cber@ .com.cn C++ C++ polymorphism OOP C++ C++/ override/redefinevirtual virtual dynamic dispatch C++ C++ software componentsflexibility, C++ overload overloaded functions 11

12 1 / virtual class jump table vtable C C++ private virtual Sakkinen92 private virtual Sakkinen92 private virtual scope name clash duplicate declaration scope ambiguity name overloading class A public: void nonvirt(); virtual void virt(); class B : public A 12

13 1 public: void nonvirt(); void virt(); A a; B b; A *ap = &b; B *bp = &b; bp->nonvirt(); //calls B::nonvirt as you would expect ap->nonvirt(); //calls A::nonvirt even though this object is of type B ap->virt(); //calls B::virt, the correct version of the routine for B objects B A B::nonvirt B C++ A::nonvirt B::nonvirt A::nonvirt B::nonvirt class B: public A public: void b_nonvirt(); void virt(); B b; B *bp = &b; bp->nonvirt(); //calls A::nonvirt bp->b_nonvirt(); //calls B::b_nonvirt B B B B A::nonvirt B::nonvirt Object-Oriented Design(OOD) strongly defined interface C++ B A::nonvirt B nonvirt B B nonvirt 13

14 1 C++ B C C nonvirt A nonvirt B::nonvirt :D C virtual nonvirtual virtual OOP a->f() a f() A A C++ f() virtual non-virtual a->f() a->f() f() a->f() C++ ARM, section 10.9c, p 232 Eiffel Java C++ Java C++ final Eiffel frozen 2 C++ virtual OOD reusable Object-Oriented Software Construct P7, Reusability, Charpter 1.2 A REVIEW OF EXTERNAL FACTORS C++ virtual virtual not actually polymorphic table 14

15 1 overhead OO C++ virtual C++ non-virtual it says that non-virtual routines cannot be redefined, If you have defined a non-virtual routine in base, then it cannot be virtual in the base whether you redefined it as virtual in descendant. Rumbaugh C++ C++ C++ method resolution / virtual virtual RBPEL91 virtual virtual virtual C++ weak object-oriented language low level details C++ mistaken overriding (duplicate declaration)c++ Simula virtual (function signature) Java virtual static, private final Java Java 15

16 1 Eiffel Object Pascal 2 Eiffel Object Pascal global analysis 3 pure virtual functions Java ( Eiffel ) deffered virtual C++ virtual Virtual class virtual table global analysis SmalltalkObjective-C, Java Eiffel Virtual C++OOP Virtual 100% 16

17 1 bugn C++ template <typename P1, typename P2> P1 add(const P1& p1, const P2& p2) return p1+p2; OK P1 P2 template <typename P1, typename P2> P2 add(const P1& p1, const P2& p2) return p1+p2; OK P1 P2 template <typename P1, typename P2> AddT<P1, P2> add(p1 x, P2 y) return AddT<P1, P2>(x,y); STL AddT AddT<P1, P2> AddT 17

18 1 template <typename P1, typename P2> class AddT public: AddT(const P1& p1, const P2& p2) : m_p1(p1), m_p2(p2) operator P1() return m_p1 + (P1)m_p2; operator P2() return (P2)m_p1 + m_p2; private: const P1& m_p1; const P2& m_p2; (int)add(3.0, 2) OK float a=1.0; float b=2.0; (int)add(a,b); P1P2 template partial specilization VC6 VC6 GCC2.95 BCC5.5.1 : template <typename P1> class AddT<P1, P1> public: AddT(P1 p1, P1 p2) : m_p1(p1), m_p2(p2) operator P1() return m_p1 + (P1)m_p2; private: const P1 &m_p1, &m_p2; 18

19 1 Traits Nathan C.Myers Nathan C.Myers 1993 ISO/ANSI C++ C++ explicit C++ Report Dr. Dobb s Journal C++ Report traits extra level of indirection Myers Translated by Chong-chong, with original author's permission. Copyright 2001 by Chong-chong & Nathan Myers. C++ Traits IOStream streambuf EOF int class streambuf... int sgetc(); // EOF int sgetn(char*, int N); // N char EOF int char wchar_t streambuf template <class chart, class intt> class basic_streambuf... intt sgetc(); int sgetn(chart*, int N); chart EOF intt intt 19

20 1 sgetc Traits chart template <class chart> struct ios_char_traits chart struct ios_char_traits<char> typedef char char_type; typedef int int_type; static inline int_type eof() return EOF; ios_char_traits<char> typedef template <class chart> class basic_streambuf public: typedef ios_char_traits<chart> traits_type; typedef traits_type::int_type int_type; int_type eof() return traits_type::eof();... int_type sgetc(); int sgetn(chart*, int N); typedef traits wchar_t ios_char_traits 20

21 1 struct ios_char_traits<wchar_t> typedef wchar_t char_type; typedef wint_t int_type; static inline int_type eof() return WEOF; traits Traits ANSI/ISO C++ floatdouble long double epsilon <float.h> FLT_MAX_EXP DBL_MAX_EXP Traits template <class numt> struct float_traits struct float_traits<float> typedef float float_type; enum max_exponent = FLT_MAX_EXP static inline float_type epsilon() return FLT_EPSILON;... struct float_traits<double> typedef double float_type; enum max_exponent = DBL_MAX_EXP static inline float_type epsilon() return DBL_EPSILON;... max_exponent float double 21

22 1 template <class numt> class matrix public: typedef numt num_type; typedef float_traits<num_type> traits_type; inline num_type epsilon() return traits_type::epsilon();... public typedef Traits typedef C++ Stroustrup Design and Evolution of C++359 traits CMP template <class T> class CMP static bool eq(t a, T b) return a == b; static bool lt(t a, T b) return a < b; template <class chart> class basic_string; compare template <class chart,class C = CMP<charT> > int compare(const basic_string<chart>&, const basic_string<chart>&); compare C chart eq lt compare 22

23 1 streambuf template <class chart, class traits = ios_char_traits<chart> > class basic_streambuf public: typedef traits traits_type; typedef traits_type::int_type int_type; int_type eof() return traits_type::eof();... int_type sgetc(); int sgetn(chart*, int N); traits Runtime-variableTraits basic_streambuf template <class chart, class traits = ios_char_traits<chart> > class basic_streambuf traits traits_; // member data... public: basic_streambuf (const traits& b = traits()) : traits_(b)... int_type eof() return traits_.eof(); traits traits_.eof() traits STL allocator Traits 23

24 1 Traits extra level of indirection A class used in place of template parameters. As a class, it aggregates useful types and constants; as a template, it provides an avenue for that "extra level of indirection" that solves all software problems. traits baggage baggage template traits traits template typename template <class chart, class traits = ios_char_traits<chart> > class basic_streambuf public: typedef traits traits_type; typedef typename traits_type::int_type int_type; int_type eof() return traits_type::eof();... int_type sgetc(); int sgetn(chart*, int N); typename Stroustrup, B. Design and Evolution of C++, Addison-Wesley, Reading, MA, Barton, J.J., and L.R. Nackman, Scientific and Engineering C++, Addison-Wesley, Reading, MA, Veldhuizen, T. " Expression Templates", C++ Report, June 1995, SIGS Publications, New York. 24

25 1 plpliuly Idioms IdiomsPOSA Pattern Architecture patternsdesign patternsprogramming language Idioms 1 protected 2 final namespace Private class NonDerivableHelper #ifdef NDEBUG NonDerivableHelper() friend class NonDerivable; #define FINAL_CLASS #else #define FINAL_CLASS : private virtual Private::NonDerivableHelper #endif class NonDerivable FINAL_CLASS... namespace 3 class MyClass private: MyClass(const MyClass& ); const MyClass& operator = ( const MyClass& ); C++ Idioms TypeTraitsSmartPointer Idioms 25

26 1 final virtual privateprotected public comp.lang.c++.moderated2001/5/15andrei Alexandrescu friend-based friend private virtual private virtual NonDerivable class D: public NonDerivable D() // class D FINAL_CLASS, public NonDerivable D() // Andrei Alexandrescu Private::NonDerivableHelper NonDerivableHelper(int) NonDerivable NonDerivable(): NonDerivableHelper(0) #ifdef NDEBUG #define FINAL_CLASS #else #define FINAL_CLASS : private virtual Private::NonDerivableHelper #endif namespace Private class NonDerivableHelper protected: NonDerivableHelper(int) //ADDED CTOR ARGUMENT class NonDerivable FINAL_CLASS public: NonDerivable() : NonDerivableHelper(0) //PASS A DUMMY VALUE 26

27 1 Smart Pointer smart pointer smart pointer pointer Class C/C++ pointer C++ strongly typed ->* smart pointer template<class T> class SmartPtr public: SmartPtr(T* p = 0); SmartPtr(const SmartPtr& p); ~SmartPtr(); SmartPtr& operator =(SmartPtr& p); T& operator*() const return *the_p; T* operator->() const return the_p; private: T *the_p; const *-> 27

28 1 C++ std::auto_ptr STL template<class X> class auto_ptr public: typedef X element_type; explicit auto_ptr(x* p = 0) throw() : the_p(p) auto_ptr(auto_ptr<x>& a) throw() : the_p(a.release()) auto_ptr<x>& operator =(auto_ptr<x>& rhs) throw() reset(rhs.release()); return *this; ~auto_ptr() throw() delete the_p; X& operator* () const throw() return *the_p; X* operator-> () const throw() return the_p; X* get () const throw() return the_p; X* release() throw() X* tmp = the_p; the_p = 0; return tmp; void reset(x* p = 0) throw() if (the_p!=p) delete the_p; the_p = p; private: X* the_p; 28

29 1 auto_ptr delete Java C++ C++ auto_ptr auto_ptr exception-safe smart pointer smart pointer auto_ptr smart pointer smart pointer SmartPtr<int> p; if(p==0) if(!p) if(p) p SmartPtr bool SmartPtr::null() const operator void* () template<class T> class SmartPtr public:... operator void*() const return the_p;... private: T* the_p; basic_ios operator void*() operator!() smart pointer smart pointer ATL CComPtr CComQIPtr COM smart pointer smart pointer 29

30 1 BCB VCL CKER Internet Windows Borland C++ Builder Delphi VCL Win32 Windows C++ Builder VCL 1 (Message Map) TObject Dispatch BEGIN_MESSAGE_MAP VCL_MESSAGE_HANDLER( ) END_MESSAGE_MAP( ) C++ CKER VCL \Borland\CBuilder5\Include\Vcl sysmac.h #define BEGIN_MESSAGE_MAP virtual void fastcall Dispatch(void *Message) \ \ switch (((PMessage)Message)->Msg) \ #define VCL_MESSAGE_HANDLER(msg,type,meth) \ case msg: \ meth(*((type *)Message)); \ break; // NOTE: ATL defines a MESSAGE_HANDLER macro which conflicts with VCL's macro. The // VCL macro has been renamed to VCL_MESSAGE_HANDLER. If you are not using ATL, // MESSAGE_HANDLER is defined as in previous versions of BCB. file:// #if!defined(using_atl) &&!defined(using_atlvcl) &&!defined(inc_atl_headers) #define MESSAGE_HANDLER VCL_MESSAGE_HANDLER #endif // ATL_COMPAT 30

31 1 #define END_MESSAGE_MAP(base) default: \ break; \ \ base::dispatch(message); \ BEGIN_MESSAGE_MAP VCL_MESSAGE_HANDLER(WM_PAINT,TMessage,OnPaint) END_MESSAGE_MAP(TForm1) virtual void fastcall Dispatch(void *Message) switch (((PMessage)Message)->Msg) case WM_PAINT: default: OnPaint(*((TMessage *)Message)); // Form1 break; TForm1::Dispatch(Message); break; 1virtual void fastcall Dispatch(void *Message) TObject BCB TForm Method Dispatch TObject VCL TObject VCL TObject Borland TObject TObject Dispatch Dispatch TObject::DefaultHandler TObject DefaultHandler 2 MESSAGE_HANDLER(WM_PAINT,TMessage,OnPaint) ATL MESSAGE_HANDLER VCL Borland VCL_MESSAGE_HANDLER ATL MESSAGE_HANDLER VCL_MESSAGE_HANDLER ATL VCL_MESSAGE_HANDLER 31