Function for C++ struct

Yes, a struct is identical to a class except for the default access level (member-wise and inheritance-wise). (and the extra meaning class carries when used with a template)

Every functionality supported by a class is consequently supported by a struct. You’d use methods the same as you’d use them for a class.

struct foo {
  int bar;
  foo() : bar(3) {}   //look, a constructor
  int getBar() 
  { 
    return bar; 
  }
};

foo f;
int y = f.getBar(); // y is 3