Classes and Objects

• [[Classes & Objects]]
• Classes define abstract characteristics of a type
• Members can be
  • Data variables
  • [[Functions & Constructors]]
• Object
  • Instance of a class
  • [[Classes and Objects ll]]
• Information Hiding Labels
  • Private
  • Public
  • Protected
• Default Parameters
  • Parameter to the constructor is optional
• Explicit Constructor
  • Avoids automatic conversion
  • [[Functions & Constructors]]
  • [[Multi-File Compilation]]
  • [[Composition and aggregation]]
• Constant Member functions
  • Examines but does not change the state of the object
  • Called accessors
• Interface is defined through the .h files
  • #include in the cpp file
  • Also referred to as declaration
• Preprocessor commands
  • Guards against multiple inclusions of .h files

// Preprocessor Statements
#ifndef _NAME_OF_FILE_
#define _NAME_OF_FILE_

/*
	Code Goes Here
*/

#endif

• Scope-resolution operators
  • symbolized by the ::
  • To identify the corresponding class to each function
  • Function signatures must match in the definition and the implementation file

// dog.h *Implementation File*

class dog{
public:
	dog();
	void setName(string n);
private:
	string name;
};

// dog.cpp *Definition File*

dog::dog(){
	name = "Jerry"; // Default Name
}
void dog::setName(string n){
	name = n;
}

• Objects are declared like primitive data types
• Standard Vector Class
  • Gives size() function
  • Can be assigned using =
• Standard String Class
  • Compares with ==, <, etc
• Keyword auto
  • You do not need to specify the type

auto i = 20
auto itr = vect1.begin();

• auto may not be used in some cases
• Pointer variable
  • stores the address of another obj in memory
  • before the variable name indicates a pointer declaration
  • type * variableName;
  • Pointers are uninitialized when declared, this may result in bugs

#cpp #review #classes #objects #code