Binary Tree output help

i have this program, that takes numbers. how can i make it take a string of characters and display it like this:

+
+ e
+ d
+ c
a b

but it looks like a tree, i dunno how to show u in this textbox

http://pastebin.com/W1XHQCAt

Add [code] tags around the tree output you want. This will preserve spaces and tabs.