C++ declaring a static object in a class

Question

I\'m trying to declare a static object of a class A that I wrote in a different class B, like this:

class A // just an example
{
    int x;
public:
    A(){          


        

Answer 1

You should initialize static var, the code:

class A // just an example
{
    int x;
public:
    A(){ x = 4; }
    int getX() { return x; }
};

class B
{
    static A obj1;  // <- Problem happens here
public:
    static void start();
};

A B::obj1; // init static var

int main()
{
    B::start();
}

void B::start()
{
    int x = obj1.getX();
}