Answer to Question #56999 in C for stella

Question

A university computer science department has a teaching assistant (TA) who
helps undergraduate students with their programming assignments during
regular office hours. The TA’s office is rather small and has room for only one
desk with a chair and computer. There are three chairs in the hallway outside
the office where students can sit and wait if the TA is currently helping another
student. When there are no students who need help during office hours, the
TA sits at the desk and takes a nap. If a student arrives during office hours
and finds the TA sleeping, the student must awaken the TA to ask for help. If a
student arrives and finds the TA currently helping another student, the student
sits on one of the chairs in the hallway and waits. If no chairs are available, the
student will come back at a later time.
Using POSIX threads, mutex locks, and semaphores, implement a solution
that coordinates the activities of the TA and the students. Details for this
assignment are provided below.