Math and array help please

What is the fastest (or easiest) way to sort an array like this:
Ok, I have an array, all strings and lets say they look like (in order, 0 to 9)
a
b
c
d

e
f

g
As you noticed, some are missing. How would I order all of those up, so they look like:
a
b
c
d
e
f
Any help please?

Give null values to the missing strings - if you want the array sorted in alphabetical order, call the null values "zzzzzzzz". Regards the actual sorting algorithm, visit Code Archives/Algorithms/Various Sorting algorithms.

Ryan