End all functions in the examples in chapter two with a return statement.
Change all foreach loops to for or while loops.
Make the find_song function in chapter 2 return when the first
matching song is found.
Make the find_song function write the number of the record
the song is on.
If you failed to get the program to work properly in the last exercise
of chapter 2, try it again now.
Make a program that writes all the numbers from 1 to 1000.
Modify the program in the previous exercise to NOT write numbers divisible by 3, 7 or 17.
Make a program that writes all the prime numbers between 1 and 1000.