What Every Programmer Should Know About Floating-Point Arithmetic
Why don’t my numbers add up?
So you’ve written some absurdly simple code, say for example:
0.1 + 0.2
and got a really unexpected result:
Maybe you asked for help on some forum and got pointed to a long article with lots of formulas that didn’t seem to help with your problem.
Well, this site is here to:
- Explain concisely why you get that unexpected result
- Tell you how to deal with this problem
- If you’re interested, provide in-depth explanations of why floating-point numbers have to work like that and what other problems can arise
You should look at the Basic Answers first - but don’t stop there!