C++, Static Object - share data

#cpp #static #share #data

Static objects are created only once before the program starts and destroyed when the program terminates. So they can be used to share data between different functions or instances of a class

class CountObject {
    static int count; //declare share data
public:
    CountObject() {
        count++;
    }
//static method, can be used without instantiating an object of the CountObject class
    static int getCount() {
        return count;
    }
};
//need to define and initilize value
int CountObject::count = 0;

then we can use it like:

CountObject a, b, c;
cout<<"nums of created objects :"<<CountObject::getCount()<<endl;

Just remember to define and initialize the static object outside of the class to ensure that only one instance is created for the entire program.
int CountObject::count = 0;

Top comments (4)

Paul J. Lucas • Jun 28 '23

Static objects are created only once before the program starts and destroyed when the program terminates.

That's true only of global static objects. For static data members as you've shown, they're initialized only before the first object of the class is created — that may be long after the program starts.