Why do i get error :Undefined reference to Class::static member_variable?[Solved]

Question

https://code.sololearn.com/cmTBam67531R/?ref=app

Answer 1

You only declared the variable, but you never actually define it. Add the following definitions after the class:

int num::positive_num = 0;
int num::negative_num = 0;

As an alternative, you can use the inline attribute to define static members directly inside the class (as of C++17, I think):

inline static int positive_num = 0;
inline static int negative_num = 0;

See the following link for more details:

https://en.cppreference.com/w/cpp/language/static

Answer 2

It's not declared as an int
https://code.sololearn.com/cQ88RpQ0D4NI/?ref=app

Answer 3

Slick thank you . I should have mentioned that i am trying to access variables inside static function.

Answer 4

Slick i am trying to access static member of class

Answer 5

Shadow thanks a lot .Previously i declared the variable but inside the class and then it gave me other error .

Looks cumbersome to define them outside of class declaration.

inline seems good .

Edit: I went through so many tutorials such as,

https://www.google.com/amp/s/www.edureka.co/blog/what-is-static-member-function-in-cpp/amp/

but never came across something like inline.