Postfix Notation: Postfix notation is a way of writing expressions without using parentheses. For example, the expression (1 + 2) * 3 would be written as 1 2 + 3 *. A postfix expression is evaluated using a stack. Scan a postfix expression from left to right. A variable or constant is pushed into the stack. When an operator is encountered, apply the operator with the top two operands in the stack and replace the two operands with the result.

Write a menu driven program to: A- Evaluate a user input postfix expressions (assume perfect user input at all times) B- Convert, display infix expressions to postfix expressions then evaluate and display the result of the postfix expression (assume perfect user input at all times) C- Reads words from a the text file (hangman.txt) in a LinkedList and use an iterator on it to displays all the words (duplicates allowed) in descending alphabetical order (4 words tab separated per line), compare the time to traverse the list using an iterator vs. using the get(index) method. D- Exit