Computer Assignment, Part $2$

Program $11$: Fibonacci Sequence

In mathematics, the Fibonacci sequence is a sequence in which each number is the sum of the two preceding ones. Numbers that are part of the Fibonacci sequence are known as Fibonacci numbers, commonly denoted Fn$.$ The sequence commonly starts from $0$ and $1,$ and the sequence begins as:

$0,1,1,2,3,5,8,13,21,34,55,89,144,...$

The Fibonacci numbers, Fn$,$ may be defined by the recurrence relation

$$ F$0=0,$ F$1=1,$

and for n $>1.$

$$ Fn $=$ Fn$+1+$ Fn$+2$

Write a recursive function to generate the nth Fibonacci number. The function takes one parameter: the current index value, and returns two results, Fn and Fn$-1.$ Upon entering the function, the current index is checked. If the index is $1$ or less, the function returns F$0=0,$ F$1=1.$ Otherwise, the function calls itself, but now sets the argument to be the index value minus one. Upon return, the function continues by adding the two returned values together to form Fn$.$ The function then returns Fn and Fn$-1.$

Write the main program that calls the Fibonacci function to compute the $30$th Fibonacci number. Using our primative library of functions, print the $30$th Fibonacci number to the terminal. Also develop the makefile to build the code into an executable.