C++ classes

c++_classes.md

Classes

data abstraction

• allow you to preform data abstraction and create new dataTypes in an Object Oriented fashion
• a place to hold data and manage operations on that data
  • holds functions that a consumer can call
• class and struct both have the same capabilities in c++
  • have members, functions, constructors
  • different defaults:
    • class all members are private
    • struct all members are public
• class is a dataType
  • have data members and member functions
  • should be placed in a .h file
• object is an instance of a class, a variable
• format:

    class nameType
    {
    	public:
    		// place member functions (prototype!)
    	private:
    		// place private data members
    }; // need a semicolon
  

modular abstraction

• extra files to better organize code
• can come in .cpp, .o, .h
• .cpp where functions go
  • implementation of code
  • #include "header.cpp"
  • a single main() function for all .cpp files
• .h is a header file that contains a class definition
  • no need to compile with g++
    • if you do, you will created a hidden .gch file and changes to .h file will not be made
    • can find these with ls -a
  • #include
  • constants
  • structs
  • prototypes
  • class interfaces
  • NOT function body
  • NOT #include .cpp files
• .o is a file that contains a pre-compiled object
  • this allows the object to be used by other files
  • hides the code secrets of the object
  • not everything is open-source in industry
• <> with #includes means system directory
• g++ *.cpp compile with multiple files
  • only works if all files are in the same directory
  • compiler does not need a file to be named anything in particular if it contains main()