CIS-255 Home: http://www.c-jump.com/bcc/c255c/c255syllabus.htm

Overview of C++ you already know

1. Hello World
2. C++ you already know
3. Stream I/O
4. Enumerations
5. User-defined types
6. Using existing classes
7. Adding functions to classes
8. A Bit of Advice
9. C++ Comments

1. Hello World

• 
  // My first C++ program
  #include <iostream>
  int main()
  {
      std::cout << "Hello, World" << std::endl;
      return 0;
  }
  
  

   

2. C++ you already know

• Control constructs:

  
      function calls
      for  while  if-else  switch
      etc.
  
  

• Native types

  
      int, float, double, char, void, bool
  
  

• Arrays and pointers

• C++ dynamic allocation syntax

   

3. Stream I/O

• 
  #include <iostream>
  
  std::cout, std::cin, std::cerr // stdout, stdin, and stderr in C
  std::endl
  
  
  

• The << and >> operators

   

4. Enumerations

• Keyword enum

• Examples:

  
      enum Suit { CLUB, DIAMOND, HEART, SPADE };
      Suit s; // enum keyword here not required
      s = CLUB; // of course
      s = (Suit) 1; // Ok, not recommended
      s = 1; // ERROR
      switch ( s ) { //...
  
      enum PrintFlags {
          COLOR = 1,
          LANDSCAPE = 2,
          TWOSIDE = 4
      };
  
  

   

5. User-defined types

• Keywords struct and class

  
      struct Point { int x; int y; };
      -or-
      class Point {
      public:
          int x; 
          int y;
      };
  
      Point p1; // Note: struct keyword not needed
      p1.x = 9;
      p1.x = 2;
  
  
  

• C supports structs. In C++ structs and classes can also have functions.

   

6. Using existing classes

• 
  #include <iostream>
  #include <string>
  using std::string;
  int main()
  {
      string s1 = "This is a string";
      std::cout
          << "There are "
          << s1.length()
          << " chars in "
          << s1
          << std::endl
          ;
      return 0;
  }
  
  

   

7. Adding functions to classes

• 
  // main.cpp
  class Point {
  public:
       // member variables
      int x;
      int y;
  
      // member functions
      void adjust( int xx, int yy )
      {
          x += xx;
          y += yy;
      }
  }; // don't forget this semicolon!
  
  int main()
  {
      // Create object 
      Point pt;
      // access to member variables
      pt.x = 5;
      pt.y = 4;
      pt.adjust( 1, 1 ); // member function call
      return 0;
  }
  
  

   

8. A Bit of Advice

• First, try being a client:

  • use existing objects where possible.

• Second, design your own classes,

  • but keep in mind the client perspective.

   

9. C++ Comments

• 
      // comments from there to end of line
  
      /*
          multi-line
          comment
      */
  
  

• Avoid mixing comments, since neither type respects the other:

  
      // this --> /* is not effective
      so this becomes an error */
      /* this --> // is not effective */ so this is an error
  
  
  

• Some compilers may give you a warning when comments are mixed.