Division with cycle remainder

Divide number and return result in form of a string. e.g 100/3 result should be 33.(3) Here 3 is in brackets because it gets repeated continuously and 5/10 should be 0.5.

The essence is to use hashmap to restore the remainder. Once a certain remainder was obtained for 2nd time, we found the recycles.

1. public class DivisionWithCycleRemainder {
4.     public static void main(String[] args){
5.         String result = divisionToString(45,17);
6.         System.out.println(result);
7.     }
9.     public static String divisionToString(int num1, int num2) {
10.         int beforeD = num1 / num2;    //the result before dot
11.         int afterD = num1 % num2;    //the result after dot
12.         if(afterD==0){
13.             return String.valueOf(beforeD);
14.         }
15.         HashMap<Integer, Integer> hm = new HashMap<Integer, Integer>();
16.         StringBuffer result = new StringBuffer(beforeD + “.”);
17.         int remainder = afterD * 10;
18.         while(!hm.containsKey(remainder)){
19.             hm.put(remainder, result.length());    //remainder never exist, insert into hm
20.             int curr_value = remainder / num2;    //result of current position
21.             result.append(curr_value);
22.             remainder = (remainder % num2) * 10;
23.         }
24.         result.insert(hm.get(remainder).intValue(), ‘(‘);
25.         result.append(‘)’);
26.         return result.toString();
27.     }
28. }