Task: Continued fraction_Arithmetic_Construct from rational number
C#: using System;
using System.Collections.Generic;

class Program
{
    static IEnumerable<int> r2cf(int n1, int n2)
    {
        while (Math.Abs(n2) > 0)
        {
            int t1 = n1 / n2;
            int t2 = n2;
            n2 = n1 - t1 * n2;
            n1 = t2;
            yield return t1;
        }
    }

    static void spit(IEnumerable<int> f)
    {
        foreach (int n in f) Console.Write(" {0}", n);
        Console.WriteLine();
    }

    static void Main(string[] args)
    {
        spit(r2cf(1, 2));
        spit(r2cf(3, 1));
        spit(r2cf(23, 8));
        spit(r2cf(13, 11));
        spit(r2cf(22, 7));
        spit(r2cf(-151, 77));
        for (int scale = 10; scale <= 10000000; scale *= 10)
        {
            spit(r2cf((int)(Math.Sqrt(2) * scale), scale));
        }
        spit(r2cf(31, 10));
        spit(r2cf(314, 100)); 
        spit(r2cf(3142, 1000));
        spit(r2cf(31428, 10000));
        spit(r2cf(314285, 100000));
        spit(r2cf(3142857, 1000000));
        spit(r2cf(31428571, 10000000));
        spit(r2cf(314285714, 100000000));
    }
}

Java: import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class ConstructFromRationalNumber {
    private static class R2cf implements Iterator<Integer> {
        private int num;
        private int den;

        R2cf(int num, int den) {
            this.num = num;
            this.den = den;
        }

        @Override
        public boolean hasNext() {
            return den != 0;
        }

        @Override
        public Integer next() {
            int div = num / den;
            int rem = num % den;
            num = den;
            den = rem;
            return div;
        }
    }

    private static void iterate(R2cf generator) {
        generator.forEachRemaining(n -> System.out.printf("%d ", n));
        System.out.println();
    }

    public static void main(String[] args) {
        List<Map.Entry<Integer, Integer>> fracs = List.of(
                Map.entry(1, 2),
                Map.entry(3, 1),
                Map.entry(23, 8),
                Map.entry(13, 11),
                Map.entry(22, 7),
                Map.entry(-151, 77)
        );
        for (Map.Entry<Integer, Integer> frac : fracs) {
            System.out.printf("%4d / %-2d = ", frac.getKey(), frac.getValue());
            iterate(new R2cf(frac.getKey(), frac.getValue()));
        }

        System.out.println("\nSqrt(2) ->");
        List<Map.Entry<Integer, Integer>> root2 = List.of(
                Map.entry(    14_142,     10_000),
                Map.entry(   141_421,    100_000),
                Map.entry( 1_414_214,  1_000_000),
                Map.entry(14_142_136, 10_000_000)
        );
        for (Map.Entry<Integer, Integer> frac : root2) {
            System.out.printf("%8d / %-8d = ", frac.getKey(), frac.getValue());
            iterate(new R2cf(frac.getKey(), frac.getValue()));
        }

        System.out.println("\nPi ->");
        List<Map.Entry<Integer, Integer>> pi = List.of(
                Map.entry(         31,        10),
                Map.entry(        314,       100),
                Map.entry(      3_142,      1_000),
                Map.entry(     31_428,     10_000),
                Map.entry(    314_285,    100_000),
                Map.entry(  3_142_857,   1_000_000),
                Map.entry( 31_428_571,  10_000_000),
                Map.entry(314_285_714, 100_000_000)
        );
        for (Map.Entry<Integer, Integer> frac : pi) {
            System.out.printf("%9d / %-9d = ", frac.getKey(), frac.getValue());
            iterate(new R2cf(frac.getKey(), frac.getValue()));
        }
    }
}