Floor of variable set to 1 returns 0

Problem Description

Adding 0.1 to a variable and displaying it as floor(variable) doesn't return 1 until it's more than 1 (though it works as expected for any other integer)

EDIT: Having done my floating point homework, I rescind my bug report.

Attach a Capx

[attachment=0:1epoa2r5][/attachment:1epoa2r5]

Description of Capx

Click the button to add 0.1 to a variable which sets one text using floor and one without.

Steps to Reproduce Bug

• Click button 10 times Observed Result floored text still says 0 until 11th click, though 2 happens at 20, 3 at 30, etc.. Expected Result 10 clicks should be 1 Affected Browsers
  • Chrome: (?)
  • FireFox: (YES)
  • Internet Explorer: (?)

Operating System and Service Pack

Vista SP2

Construct 2 Version ID

173 (apologize if this has already been addressed in newer release)

Actually, upon further inspection, 2, 3, and 4 and apparently numbers > 20 seem to work as expected and all other integers do what's described here.

Check in the debugger. Your value is actually 0.9999999999999999 but being displayed as 1 in the top textbox.

Change it to Text: Set text to str(variable1) for much amusement

Edit: So looks like the 'auto int-to-string' conversion is rounding up..

how strange...

all this time, I thought .1 + .1 + .1 was .3

math is even harder than I thought!

(You're right, I'm amused...)

how strange...

all this time, I thought .1 + .1 + .1 was .3

math is even harder than I thought!

(You're right, I'm amused...)

The joys of floating point numbers. A good wakeup call for all of us though

So is this the kind of thing that can't really be fixed? Cause it gets ugly fast in some pretty simple situations..

There's nothing really to fix, rounding error is inherent. You have to work around the limitations.

Edit: I haven't worked with much numerical stuff in C2 so I'm not sure all the available facilities.

So what you're saying is when it comes down to the final battle between machines and humans, our best defense will be floating point numbers?

Yessss.. and viruses..

Or pose them a paradoxical question... smoke issues forth.. etc.

Closing, see "Expecting math calculations to be exact" in common mis-used events and gotchas.

In binary floating-point representation, 0.1 is a recurring decimal (like one-third in base 10 is recurring forever as 0.333333333....). Naturally with a limited precision some rounding happens. This happens at the CPU level and affects all software on your system.