Plus/minus action with decimal numbers in variables

GDevelop general Bugs reports
1

Hi there! I’m continuing learn GDevelop and find a strange bug. If I do a plus/minus action with decimal numbers in variables, GDevelop change number a little less. Example: if i do -0.1 with variable=1, i get not a 0.9 but 0.900000000000001. With plus action GDevelop works same way. But if value is 0.5 - GDevelop works perfect.

Example in project: dropbox.com/s/k9wkevrwu6vhw … g.gdg?dl=0

2

It is not a bug, it’s an approximation error: The machines represent the numbers with a binary fraction, but not every base 10 number can be represented with base 2 (0 and 1), so you get an approximation :slight_smile:
You can read some of this here:
Floating Point Arithmetic: Issues and Limitations
I know it’s Python, but it’s the same for C++ and GD :wink: