It's actually quite common to have a function call pass one parameter, where the parameter is calculated using infix notation. Thus, there's a rule to simplify this common case (the prefix {} rule). So factorial
The idea is to use thestack data structureto convert an infix expression to a postfix expression. The stack is used to reverse the order of operators in postfix expression. The stack is also used to hold operators since an operator can’t be added to a postfix expression until both of its...