Recursion Puzzles

String puzzles. Some of them are too easy; some of them are too hard. But they are all about strings.

There are solutions.

1. Given a string, get the character at position 3.
2. Print all characters one at a time.
3. Print out a String.
4. Remove the character at position 3.
5. Count the letter 'i'.
6. Remove the letter 'i' the first place it appears
7. Remove all of the letter 'i'
8. Convert a string to lowercase
9. See which string comes alphabetically first
10. See if a string contains all 26 letters
11. Reverse a string
12. Find a_b where _ is any letter
13. Count the number of vowels