[Closed] Numerical Comparison

The wonderful world of single precision floating point calculations.
You can read on Wikipedia about how 32bit computers represent floating point numbers internally to get an idea why 1.1-1.0 is not really precisely 0.1.

Here is an example:

a = 0.1 
 0.1
 b = 1.1-1.0 --this causes an imprecision, the value in b is not perfectly 0.1
 0.1
 a==b
 false
 a-b
 0.0
 formattedPrint a --formatted print reveals the two values are not exactly the same
 "1e+008"
 formattedPrint b
 "1.0000002e+008"
 
 a = 0.1 * 10^9 --if you multiply by extremely large numbers, it becomes visible too
 1e+008
 b = (1.1 - 1.0)*10^9
 1e+008
 a==b
 false
 a-b
 -24.0
 
 close_enough a b 10 --this method should be used in such cases
 true
 
 a as string == b as string --or you can compare their printed representation
 true
 
 
 c = 0.1 --when both specified explicitly, no problem
 0.1
 d = 0.1
 0.1
 c==d
 true