Please write the code in c programming language. Please provide enough explanation on the code so that i can understand it.

In this homework, youll measure the costs of a system call and context switch. Measuring the cost of a system call is relatively easy. For example, you could repeatedly call a simple system call (e.g., performing a 0-byte read), and time how long it takes; dividing the time by the number of iterations gives you an estimate of the cost of a system call. One thing youll have to take into account is the precision and accuracy of your timer. A typical timer that you can use is gettimeofday(); read the man page for details. What youll see there is that gettimeofday() returns the time in microseconds since 1970; however, this does not mean that the timer is precise to the microsecond. Measure back-to-back calls to gettimeofday() to learn something about how precise the timer really is; this will tell you how many iterations of your null system-call test youll have to run in order to get a good measurement result. If gettimeofday() is not precise enough for you, you might look into using the rdtsc instruction available on x86 machines.