Hello Perl Monks -

I am a new user to this site - but a professional programmer for many years - hope I can be a vital contributor to your esteemed collection of knowledge.

I have a simple math question.

I recently stumbled upon a very obscure problem in one of my apps.

According to Perl,

100.10 - 100.00 = 0.0999999999999943

and not ".10" as I would have imagined from my early school days.

Try it yourself in your favorite shell (this happens in v5.83):

perl -e "print (100.10-100);"

Can someone with supreme wisdom please explain to me why perl comes to this result from simple math with a non-whole number. This is causing thousands of calculations in my app to be off by .01 - .02 - but when money is involved it needs to be 100% correct.

Is this a perl bug? Or am I missing something completely obvious?

Look forward to your replies.