Please help me in decoding this

[Jemoh]

I don't understand line 9 & 13 at http://pastebin.com/WErmnAG5

[Ingolme]

+= is a shorthand operator, it represents adding a value to a variable and assigning the result to itself.$tax += 4 is equivalent to $tax = $tax + 4 You'll have to look at the documentation for printf() for an explanation of the parameters. The format is explained properly in the sprintf() reference page.