Java code:

Design an implementation for CityCode classes (abstract parent class, the

isValid method is abstract), MexicoCode and USCode which are the subclasses

Concrete of CityCode. Make sure to include the instance variables as well as

the builders. The appendix below presents a summary of the class methods

String and Character.

Create a Test class to test your classes:

Declare a table, named codes, which can contain 100 postal codes;

Create n = 10 postal codes some of which are american codes while others

will be mexican codes. Likewise, some codes are valid and others are not.

Finally, save these codes in the first n cells on the left of the table;

Knowing that exactly n postal codes are in the left part of the table,

write a for loop to count the number of valid codes and display it.

/ Example output * /

2 codes are valid

Appendix

The String class contains the following methods.

char charAt (int cod): returns the character located at the position specified by the index

cod;

int length (): returns the length of this string.

The Character class contains the following methods:

static boolean isDigit (char char): determines if the character passed in parameter is a

number;

static boolean isLetter (char char): determines if the character passed in parameter is a

letter;

static boolean isWhitespace (char char): determines if the character passed in parameter is a

white space.