Question

here’s the snippet in java:

class C {

    private static int c = 0;

    C(){ c++; }

    public static int getC () { return c; }
}

public class TestC {

    public static void main (...) {

        C c1 = new C();
        C c2 = new C();

        // at this point C.getC() returns 2(int)
    }
}

now I want to do something similar in C++, I have a basic understanding of class writing,
what should be the shortest snippet of code to implement the counter ?

here’s my example class:

class C {

    public:


    private:
}

int main () {

    C c1;
    C c2;

    // printing the counter like C.getC();
}

Answer 1

Very similar.

In relevant header:

class C {   
    private:
         static int c;  // Declaration of c.
    public:
         C(){ c++; }
         static int getC () { return c; }
};

In one .cpp file:

int C::c = 0;  // Definition of c.

It’s crucial to provide the definition of c in exactly one place (i.e. not in a header) or you will get linking errors.