Stop saying "It didn't work", without supporting documentation of the failure. You did it here, and here, and here; three times out of nine posts. "It didn't work" is absolutely useless information, and gets you no closer to a solution. Here's how that sort of post should look:

I tried to incorporate your suggestion into my code, but it didn't work as I intended. Here's my code:

# 5 to 20 lines of code that can compile, and
# that shows the failure.
[download]

Here is the sample input:

# A few lines of characteristic input.
[download]

And here is the output I'm getting:

# A few lines of output that the code you posted produces with the inp
+ut you posted.
[download]

And here is what I would like it to produce:

# A few lines of output that the posted input should result in if the 
+code were working ok.
[download]

With that sort of thorough problem description, you will get more useful answers, more quickly.