You have been hired by the CS Department to write code to help synchronize a professor and his/her students during office hours. The professor, of course, wants to take a nap if no students are around to ask questions; if there are students who want to ask questions, they must synchronize with each other and with the professor so that

- only one person is speaking at any one time,

- each student question is answered by the professor, and

- no student asks another question before the professor is done answering the previous one.

You are to write four procedures: AnswerStart(), AnswerDone(), QuestionStart() and QuestionDone().

The professor loops running the code: AnswerStart(); give answer; AnswerDone(). AnswerStart doesnt return until a question has been asked. Each student loops running the code: QuestionStart(); ask question; QuestionDone(). QuestionStart() does not return until it is the students turn to ask a question. Since professors consider it rude for a student not to wait for an answer, QuestionEnd() should not return until the professor has finished answering the question. You can use a command line interface for this program. You are free to make other design choices and be creative in your implementation. You may use any programming language of your choice.