import java.util.ArrayList; public class FractionManipolo { /* * Hello Coder, * here is a task for the weekend. * Write a program that converts * fractions like 1/3 or 27/1234 or * 5/96 into a decimal fraction. * The result should look like this * examples: * ------------------------------------- * Your task is write a method of | * compute the period length. And | * change the output (???) to the right| * periodic length. | * ------------------------------------- */ public static void main(String[] args) { // change maxDigits for more or less decimal places. showResultOf(1, 3, 10); // numerator, denominator, decimal places showResultOf(27, 1234, 100); showResultOf(5, 96, 30); } public static void showResultOf(int numerator, int denominator, int maxDigits) { if(isPeriodicalFraction(denominator)) { String text = "The fraction %s/%s has the peroid length (???) after %s nonperiodic points.%n"; System.out.printf(text, numerator, denominator, getNonperiodicPoints(denominator)); } String frac = divid(numerator, denominator, maxDigits); String text = "In decimal notation %s%n%n"; System.out.printf(text, frac); } public static boolean isPeriodicalFraction(int denominator) { ArrayList a = PFZ(denominator); for(int i = 0; i < a.size(); i++) { if(a.get(i) != 2 && a.get(i) != 5) return true; } return false; } public static int getNonperiodicPoints(int denominator) { ArrayList a = PFZ(denominator); int countTwo = (int) a.stream().filter(x -> x % 2 == 0).count(); int countFive = (int) a.stream().filter(x -> x % 5 == 0).count(); return countTwo < countFive ? countFive:countTwo; } /** * The Integer Factorial method with such many decimal places are you want * The result are not rounded. * @param numerator * @param denominator * @param maxDigits many decimal places are you want * @return the result is a Decimal Number as a String */ public static String divid(int numerator, int denominator, int maxDigits) { if(denominator == 0) throw new ArithmeticException("division by zero not allowed."); if(numerator == 0) return "0"; int z = numerator; int n = denominator; int count = 0; String fraction = ""; do { int x = z / n; fraction += "" + x; if(!fraction.contains(".")) fraction += "."; z = z % n; if(z == numerator && count > 0) return computeNiceResult(fraction, denominator); if (z == 0) return computeNiceResult(fraction, denominator); z *= 10; } while (count++ < maxDigits); return computeNiceResult(fraction, denominator); } private static String computeNiceResult(String fraction, int denominator) { if(fraction.endsWith(".")) return fraction.substring(0, fraction.length()-1); if(isPeriodicalFraction(denominator)) return fraction + " period"; return fraction; } /** * isPrime(number) return true if number is a prime-number * @param number * @return true if prime else false */ public static boolean isPrime(long number) { if (number == 2 || number == 3) return true; if (number % 2 == 0 || number < 2) return false; long sqrt = (long) Math.sqrt(number) + 1; for (long i = 3; i < sqrt; i += 2) if (number % i == 0) return false; return true; } /** * PFZ is meaning "Prime-Factor-Separation" * @param n the number to analysis * @return an Array of the Prime Factors of n */ public static ArrayList PFZ(long n) { ArrayList result = new ArrayList<>(); long N = n; long i = 2; while(i <= N) { if(isPrime(i) && N % i == 0) { result.add(i); N /= i; } else i++; } return result; } }