C++，使用 class 名称调用 function

Question

In C++ how may I write a function that is being called using the class name? for example if I have a class called test I want to call a function called calc like this:

test::calc();

and not via an object of the class.

Answer 1

class test{
public:
   static void calc(){ /*do stuff */ }
};

See static members

Answer 2

 class Test {
 public:
     static void calc() { /* ... */ }
 };

 int main() 
 {  
    Test::calc();
 }

Essentially an ordinary function within the namespace of the class.