Converting Decimals to Fractions

Question

Hi everyone,

I am trying to convert decimal numbers to fractions. I did manage to get something working but then hit the problem of handling negative decimals.

Does anyone have a way of converting decimals to fractions? I need something to convert the following

decimal         convert to      fraction
1.2                                   1/5
1.36                                 4/11
2.25                                 5/4
etc etc

If you have anything I could use or better still point me towards an article that would be great. I have tried google but found nothing suitable :-(

Many thanks in advance
Colin

Mike Gold · Answer

The first parameter is the larger of the numerator and denominator, the second is the smaller of the numerator and denominator. It will return the least common denominator. You can divide top and bottom by this number.

Colin Adan · Answer

Mike, I think I'm missing something. I think I understand what the function is doing and I understand the need to multiply to get rid of the decimalisation in the original number. But the fuction takes two parameters. The first is surely the normalised decimal, but what is the second parameter? Many thanks again, Colin

Colin Adan · Answer

Mike, Very many thanks indeed Regards, Colin

Mike Gold · Answer

1) multiply the number by 10 until there are no more fractions. 2) Track the multiple 3) Then use Euclid's gcd (greatest common denominator) algorithm on the numerator and denominator (see below) to determine what to divide the numerator and denominator by. function extended_gcd(a, b) if a mod b = 0 return {0, 1} else temp := extended_gcd(b, a mod b) x := first(temp) y := last(temp) return {y, x-y*(a div b)} for recurring fractions (e.g. .33333333) use recurring number / (base 10 number - 1) so for .33333 this would be 3/(10 - 1) = 3/9 = 1/3 or 333/(1000 - 1) = 333/999 = 1/3