Trouble initilizing static variable.

[BroBuilder]

I am trying to initialize the variable count, which I declare in the class Count. However, I have tried doing it in multiple places in multiple ways and it does not work.

Main file:

  
#include <iostream>
#include "Count.h"

using namespace std;

int main() {
// putting Count::count = 0; here doesn't work.
	Count test1;
	test1.information();
	return 0;
}

Count.cpp:

#include "Count.h"

Count::Count() {
// why can't I say count = 0; here?
// Count::count = 0; doesn't work either.
	Count::count = 0;
}

Count::~Count() {

}

Count.h:

#ifndef COUNT_H_
#define COUNT_H_

#include <iostream>

using namespace std;

class Count {
public:
	static int count;
public:
	Count();
	virtual ~Count();
	void information(){
			cout << count << endl;
		};
private:

};

#endif /* COUNT_H_ */

[dutch]

You need to initialize it globally in the cpp file for the class:

// near top of count.cpp, globally:
int Count::count = 0;

[seeplus]

or as C++17 just mark count as inline and set it's initial value.

As one file:

#include <iostream>

using namespace std;

class Count {
public:
	inline static int count {};
public:
	Count();
	virtual ~Count();
	void information() {
		cout << count << '\n';
	};
private:

};

Count::Count() { }
Count::~Count() { }

int main() {
	Count test1;
	test1.information();

	Count::count = 11;
	test1.information();
}

0
11

[Ganado]

Count::Count() {
// why can't I say count = 0; here?
// Count::count = 0; doesn't work either.
Count::count = 0;
}

Just to explain some reasoning here: static variables exist independently of any instance of the class. So the initialization of the variable can't rely on the constructor for a particular object being called.

[BroBuilder]

Thank you for your help.