Q:

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

belongs to collection: C++ Classes and Object programs

mahmoud2506
Save to bookmark
|
2022-05-05
|
  309 
0

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

Static data member

A static data member is also known as "Class Member" and it is available for all classes. In other words – we can say "A static data member is just like a global variable for a class". Generally, static data members are used to maintain the common things related to the class, like counting the objects etc.

Static Member Function

A static member function is used to access or manipulate the static data member, other data member cannot be used with a static member function.

C++ programming, exam questions, C++ programming exam-questions,
login and add your own answer to this question

All Answers

mahmoud2506
2022-05-05
need an explanation for this answer? contact us directly to get an explanation for this answer

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

need an explanation for this answer? contact us directly to get an explanation for this answer

total answers (1)

C++ Classes and Object programs
This question belongs to these collections

Similar questions

need a help?

find thousands of online teachers now
Create an object of a class inside another class d... >>
<< C++ program to demonstrate example of friend funct...