Fibonacci (optional)

This is an optional assignment and can be a little tricky. The Fibonacci sequence is an infinite sequence of numbers that starts with 0 and 1 and then adds the previous number with the current to get the next number.

round 1:
0 <-- previous
1 <-- current
1 <-- new

round 2:
0
1 <-- previous
1 <-- current
2 <-- new

This sequence has many real-world applications and is even a naturally occurring phenomenon in plants and animals. This assignment will not introduce you to any real-world applications but is a fun puzzle to solve that will allow you to flex your new loop-building muscles.

Setup

Fork the following repository and clone your copy (if you haven't already for this lesson).

Fibonacci

Open fibonacci.py in your text editor.

Requirements

General

• ask the user if they want to:

  1) calculate the nth Fibonacci number
  2) calculate the last Fibonacci number less than or equal to n
  3) quit

Loops

• solve the selected option using loops. Each option lends itself more to a

  certain loop type. It is your job to find out which one goes with which

Tips

• the first 10 Fibonacci numbers are:

  0 1 1 2 3 5 8 13 21 34

• an efficient algorithm will require you to swap the values of two variables.

  You can do this using a temporary variable. Since this is a bit tricky, I will

  provide you with the part you will need.

  temp = current
  current += previous
  previous = temp