Count the created objects using static member function in C++

Program:

This program is implemented to count the total number of created objects with the help of static data member and static member function.

• A static data member needs to be declared first that we declared in private section: Example: static int count;
• To count the object, data member count must be incremented by 1, that we have done in the constructor because the constructor is invoked when a new object is created.
• To print the total number of created objects, we created a static member function named totalObjects() which is returning the value of count.
• Final and important thing – A static data member must be initialized outside of the class with the class name. Example: int Message::count =0;

  #include <iostream>
  #include <string.h>
  using namespace std;
  
  class Message
  {
  	private:
  		char str[30];
  		//static data member to count the objects
  		static int count;
  		
  	public:
  		//constructor
  		Message()
  		{
  			count++;
  		}
  		
  		//member function to initialise message
  		void initMessage(char s[])
  		{
  			strcpy(str,s);
  		}
  		
  		//member function to print message
  		void printMessage(void)
  		{
  			cout << str << endl;
  		}
  		
  		//static member function
  		static int totalObjects(void)
  		{
  			return count;
  		}
  };
  
  //initialise static member function
  int Message::count =0;
  
  //main function
  int main()
  {
  	Message M1;
  	Message M2;
  	Message M3;
  	
  	M1.initMessage("Message one");
  	M2.initMessage("Message two");
  	M3.initMessage("Message three");
  	
  	M1.printMessage();
  	M2.printMessage();
  	M3.printMessage();
  	
  	//printing object count 
  	cout << "Total objects created: " << Message::totalObjects() << endl;
  	
  	return 0;
  }

Output

Message one
Message two
Message three
Total objects created: 3