C++ -- is much more than a better C

C 



   1972   C  Kernigan and Ritchi (Unix) 
   1983   C++   (Simula 1967)
   1985   ANSI/ISO C
   1996   ANSI/ISO C++

Design principles -- the benefits of efficiency
  • superset of C -- supporting OOP
  • static typing -- with user-defined exceptions
  • explicit -- no default virtual functions
  • extensible -- libraries in C and C++
slide: The language C++

Keywords:

C++ overview


  • inline, new, delete, private, protected, public

Language features:
  • constructors -- to create and initialize
  • destructors -- to reclaim resources
  • virtual functions -- dynamic binding
  • (multiple) inheritance -- for refinement
  • type conversions -- to express relations between types
  • private, protected, public -- for access protection
  • friends -- to allow for efficient access
slide: C++ -- terminology (1)

Some basic terminology

name -- denotes an object, a function, set of functions, enumerator, type, class member, template, a value or a label

object -- region of storage

slide: C++ -- terminology (2)

Type expressions
slide: C++ -- expressions (1)

Expressions
  • operators -- + , - ,.., < , <= ,.., == , != ,.., && , ||
  • indexing -- o[ e ]
  • application -- o(...)
  • access -- o.m(...)
  • dereference -- p->m(...)
  • in/decrement -- o++, o--
  • conditional -- b?e1:e2

Assignment
  • var = expression
  • modifying -- +=. -=, ...
slide: C++ -- expressions (2)

Control
slide: C++ -- control

ADT in C style

 

  struct ctr { int n; }
  
  void ctr_init(ctr& c) { c.n = 0; }
  void ctr_add(ctr& c, int i) { c.n = c.n + i; }
  int ctr_val(ctr& c) { return c.n; }

Usage

 

  ctr c; ctr_init(c); ctr_add(c,1); 
  ctr* p = new ctr; ctr_init(*p); ctr_add(*p);
slide: C++ -- objects (1)

ADT in C++

 

  class ctr {
  public:
     ctr() { n = 0; }  // constructor
     ~ctr() { cout << "bye"; }; // destructor
     void add( int i = 1) { n = n + i; }
     int val( ) { return n; }
  private:
  int n;
  };

Usage

 

  ctr c; c.add(1); cout << c.val(); 
  ctr* p = new ctr(); c->add(1); ...
slide: C++ -- objects (2)

Inheritance

 

  class A { 
   ancestor  

  public:
  A() { n = 0; }
  void add( int i ) { n = n + i; }
  virtual int val() { return n; }
  protected: // private would deny access to D
  int n;
  };
  
  class D : public A { 
   descendant  

  public:
  D() : A() { }
  int val() { return n %  2; }
  };
slide: C++ -- inheritance

Techniques
slide: C++ -- techniques (1)
 


  class ctr { 
   C++  

  public:
  ctr(int i = 0, char* x = "ctr") { 
  	n = i; strcpy(s,x); 
  	}
  ctr& operator++(int) { n++; return *this; }
  int operator()() { return n; }
  operator int()   { return n; }
  operator char*() { return s; }
  private:
  int n; char s[64];
  };

Usage

 

  ctr c; cout << (char*) c++ << "=" << c();
slide: C++ - techniques (2)

The language C++

C


slide: C++ -- summary