# Functions 2

- Numbers passed by reference
- Array passed by value or by reference
- TODO: pass by value, pass by reference
- Variable declaration outside of functions
- Exercise: Fibonacci series
- Exercise: Permutations
- Exercise: 100 doors
- Solution: Fibonacci series
- Solution: Fibonacci recursive
- Solution: single counter
- Solution: Permutations
- Solution: 100 doors
- TODO return array