Fibonacci Exercise

For this assignment you will write a program which calculates the nth Fibonacci number. If you need a refresher on Fibonacci numbers, see here:

https://en.wikipedia.org/wiki/Fibonacci_number

Organization

The only file that was included with this assignmet is README.txt, which contains a link to these instructions. You will have to create the rest of the files yourself. See the last activity and the example code for guidance on how to organize your code and to write the Makefile.

Your program must be organized in the following files:

• fibonacci.h - Contains the prototype and documentation for your fibonacci() function, with an include guard.
• fibonacci.c - Contains the implementation of your fibonacci() function.
• main.c - Contains main() which gets the value of n from the user, uses your fibonacci() function to calculate the nth Fibonacci number, and prints it out.
• Makefile - Builds the project to create the executable fibonacci. Creates the object file fibonacci.o, which is then compiled and linked with main.c. This file has no extension, it is simply called Makefile.

fibonacci()

Your fibonacci() function must have the following prototype:

unsigned long fibonacci(unsigned int n);

Above your prototype, write a comment which contains documentation for the function. As I have done for the functions you have written recently, describe what the function does, what the parameter is, and what the return value is.

Fibonacci numbers are non-negative and get large quickly, so unsigned long is a good choice for the return type. n will be non-negative as well but will not be nearly as large as the return value, so unsigned int will work fine for n.

The 0th Fibonacci number is 0, the 1st Fibonacci number is 1, and all the Fibonacci numbers after that are calculated by adding the previous 2 Fibonacci numbers together. So when n is 0 or 1 your function can immediately return the appropriate value. Otherwise you will use a loop which continually calculates the next Fibonacci number until you reach the nth. To accomplish this you need to keep track of the previous 2 values. In the body of the loop you will calculate the next value, and then update the values of the previous 2 values appropriately.

Include Guard

Every header file should have an include guard to prevent problems with multiple inclusion. So your fibonacci.h must begin with this:

#ifndef FIBONACCI_H
#define FIBONACCI_H

and end with this:

#endif

main()

In main() you will need to print out the value that fibonacci() returns. You need to use %lu as the format specifier to print out an unsigned long value.

Your main() will not be tested by git-keeper, but it will be graded for organization.

Submission

Push your submission to git-keeper. Make sure you do not add any extra files (such as the .o files and the executable) with git add.

In addition to passing the tests, you will also be graded on organization (your code must be organzied as described above).