title: How can I call a variable from a class to another class?
body: <p>For example,
  i have class a,b,c,d,e,f.
  and for class f, they have many variable,
  so how can I call class f variable when i am in class a,b,c,d,e?
  Use import? or use static variable?
  Can static variable change while programming?
  Thank you.</p>