Question

I am doing some float manipulation and end up with the following numbers:

-0.5 -0.4 -0.3000000000000000004 -0.2000000000000000004 -0.1000000000000000003 1.10E-16 0.1 0.2 0.30000000000000000004 0.4 0.5 

The algorithm is the following:

var inc:Number = nextMultiple(min, stepSize); trace(String(inc));  private function nextMultiple(x:Number, y:Number) {     return Math.ceil(x/y)*y; } 

I understand the fact the float cannot always be represented accurately in a byte. e.g 1/3. I also know my stepsize being 0.1. If I have the stepsize how could I get a proper output?

The strange thing is that its the first time I’ve encountered this type of problem. Maybe I dont play with float enough.

Answer 1

A language agnostic solution would be to store your numbers as an integer number of steps, given that you know your step size, instead of as floats.

A non-language agnostic solution would be to find out what your language’s implementation of printf is.

printf ('float: %.1f\n', number);