code: public int find(String string) {
          if (m_strings == null) {
              return -1;
          }
  
          for (int i = 0; i < m_strings.length - 1; i++) {
              if (m_strings[i].equals(string)) {
                  return i;
              }
          }
  
          return -1;
      }
docs: Finds index of the string.
  Returns -1 if the string was not found.