The idea behind this small project is to put in practice some concurrency programming using C.
This function is the entry point (our main one). It basically calls two functions, g(x) and h(x), and both functions should be called in separated processes by using the fork() system call.
This is called in our first child process, created by f(x). This function should not call any extra fork(). We'll consider its calculation is simple enough to run in a single process.
This is called in our second child process, created by f(x). This function should call two more functions, i(x) and l(x). The i(x) should run in the same process, but a new process should be created for l(x) using fork().
This is called in the same process as its caller, h(x). We'll consider its calculation is simple enough to run in a single process.
This is called in our third child process, created by h(x).
/* Main process (P1): */
f(x) = g(x) + h(x)
/* 1st child process (P2): */
g(x) = x!
/* 2nd child process (P3): */
h(x) = i(x) + l(x)
/* 3rd child process (P4): */
i(x) = x² / sqrt(x)
/* 4th child process (P5): */
l(x) = (x! - (x²)!) / sumatory(x, 1, i²)