1903. Largest Odd Number in String

class Solution {
public:
    string largestOddNumber(string num) {
      int i = num.length() - 1;

      while(i >= 0 && ((num[i] - '0') % 2 == 0))
      {
          i--;
      }
      
      string ans = "";

      for(int j=0; j<=i; j++)
      {
          ans += num[j];
      } 

      return ans;
    }
};