C++ calculates the source code of countdown
The following content is about C++ countdown, which should be of great benefit to you.
# include
Using namespace std
Class Var
Class Base {
Public:
Virtual ~ Base () {}
Virtual ostream & print (ostream & o) const = 0
}
Ostream & operatorclone ();}
{return Expr (new Times (e1.e-> clone (), e2.e-> clone ());}
Ostream & operator
