How to declare a global variable that could be used in the entire program

Question

I have a variable that I would like to use in all my classes without needing to pass it to the class constructor every time I would like to use it. How would I accomplish th

Answer 1

The below solution should be simple enough as per the title "How to declare a global variable that could be used in the entire program " . If you want to use it in a different file then make use of extern keyword.

Please let me know if there is any issue with the solution

#include

using namespace std;

int global = 5;

class base {
    public:
        int a;
        float b;
        base (int x) {
            a = global;
            cout << "base class value =" << a << endl;
        }
};

class derived : public base {
    public:
        int c;
        float d;
        derived (float x, int y) : base (y)
        {
            d = global;
            cout << "derived class value =" << d << endl;
        }
};


int main ()
{
    derived d(0,0);
    cout << "main finished" << endl;
    return 0;
}