Idiom #348 Convert a decimal value into a fraction
Parse a number, a, into a mathematical fraction, f.
For example, 0.5 is `1/2`, and 3.125 is `3 1/8`.
https://en.wikipedia.org/wiki/Fraction
import static java.lang.Integer.parseInt;
import static java.lang.Math.pow;
import static java.lang.String.valueOf;
String s = valueOf(a), f;
s = s.substring(s.indexOf('.') + 1);
int n = parseInt(s);
if (n == 0) f = valueOf((int) a);
else {
class GCF {
static int of(int a, int b) {
return b == 0 ? a : of(b, a % b);
}
}
int d = (int) pow(10, s.length()),
gcf = GCF.of(n, d),
i = (int) a;
if (gcf != 0) {
n = n / gcf;
d = d / gcf;
}
if (i != 0) f = "%d %d/%d".formatted(i, n, d);
else f = "%d/%d".formatted(n, d);
}
let s = a.toString(), f, n, i
i = s.indexOf('.')
if (i == -1) i = s.length - 1
s = s.substring(++i)
n = parseInt(s)
if (!n) f = Math.trunc(a)
else {
let gcf = (a, b) => !b ? a : gcf(b, a % b),
d = Math.pow(10, s.length),
v = gcf(n, d)
i = Math.trunc(a)
if (v) {
n = n / v
d = d / v
}
if (i) f = `${i} ${n}/${d}`
else f = `${n}/${d}`
}