[craftyguy]

>Actually it's possible to represent 1/3 perfectly accurately

I'm curious, how?

[ars]

> I'm curious, how?

As 1/3 - exactly as it's on your screen. All rational numbers can be represented exactly.

[craftyguy]

Hmm, yes, it can be represented in ASCII. But you still have to approximate when storing it in a way that is actually useful for computation using a finite number of bits.

[dragonwriter]

Many real programming languages support arbitrary precision decimal and/or rational numbers.

Sure, there are times when space or speed concerns favor inexact representation over correctness, but that's an optimization that ought to be properly evaluated; the fact that lots of languages are designed in a way which makes it the default everyone reaches for contributes to lots of errors.

[umanwizard]

    struct rational {
        int numerator;
        int denominator;
    };

[mamcx]

And another dumb questions:

Is possible to convert to rationals in calculations?

So if I do:

1/3 + 4 + sum / total it record values properly?

[dreamcompiler]

Yes. Common Lisp is an example of a language that can represent rationals exactly and do arithmetic on them. You can avoid floating-point precision loss by using this method. But there are drawbacks: 1) The numerator and denominator will often turn into bignums as a calculation progresses, consuming ever-larger amounts of space and time, and 2) This won't help you with any calculation involving irrationals, except to prevent your initial imprecision from growing larger.