NotesCPPDayThree.txt

Day 3:
======
	Different types of members in a class
		Data Members:
		-------------
			Class Member: 
				one copy per class ---> using static keyword
			
			Object/Instance/variable Member:
				Each object has its own copy 
					normal data members without any keyword
					const data members using const keyword
					mutable data members using mutable keyword
					
			Let me give you an example
					Example: class Employee


Now Try This....
		
		class Array{
			int arr[SIZE];
			const int size;
		public:
			Array(int = 0);
			Array(int sz, int first);
			
			void fillArray(int first);
			void printArray();
		};
		
		
After this :
------------
	const member functions	and const objects 
	mutable and static members
		static members of a class are referred to class members 
		One copy Per class 
		Static member functions can access only static data members of the class 
		Static member functions cannot access instance members 

		Syntax:	
			static returnType funName(arguments){
			
			}
			
		
	dynamic memory allocation in C++	
		Heap based objects/variables allocated dynamically 
		
		C style:
		--------
			In C we used stdlib.h which has functions like malloc, calloc, realloc and free functions for allocating memory dynamically
			
		C++ style:
		==========
			Remember(always) all Valid C code is a C++ Code!. In addition to the above mentioned functions C++ provides operators new and delete for dynamic memory alocation.
			
				
			C Style:
			
				int *iPtr = malloc(sizeof(int));
				*iPtr = 10;
			
				free(iPtr); ---> For deleting / removing the memory 
			C++ Style:
				int *iPtr = new int(10); 
					For storing individual elements (on data only)
			
				delete iPtr;
			========================================================
			For collections of elements:
			C Style:
				int size = 100;
				 int *iPtr = malloc(sizeof(int) * size);
				 or 
				 int *iPtr = calloc(sizeof(int), size);
				
				free(iPtr);
			C++ Style:
				int size=100;
				int *iPtr = new int[size];
			
				delete[] iPtr;
			
	Implement this!....		
			
			
		class Array{
			int *arr; //a pointer variable
			const int size;
		public:
			Array(int = 0);
			Array(int sz, int first);
			
			void fillArray(int first);
			void printArray();
		};
		
		For any Class in C++, 
		
			your compiler provides necessary sytax support for 
				1. default object creation (Default Constructor)
						Array obj;
				2. Support copy sematics	(Copy Constructor)	
						Array objB = objA;
				3. Supports copy assignment (Assignment operator overload)
						objB = objA;
				4. Support basic destructors  (Destructor)
						
				These above functionalities are provided for every class created in C++. 
				Your C++ compiler generates constructors and destructor IF NECESSARY(when is this case considered). 
	Reading on this...			
				Deep Copy and Shallow Copy...
				=============================
					We will have discussion tomorrow
					
					
					
				
				
				
					
		
			
			
			
			
			
			
			
			
			
			
			
			
			
			
		
		
		
		
	Introduction to Operator overloading