Introduction - If you have any usage issues, please Google them yourself
A telephone number (expressed with the area code and number of requirements, such as 01068911205) of the Phone class, which should be a constructor parameter string that represents a phone number. Required to achieve the corresponding set and get function were set up and get the phone number in the code (area, 010) and number (number, 68911205), Object.toString () function to rewrite print out the entire phone number. (hint: you can use functions such as String.indexOf () and String.substring ()