A GUI application's constructor is responsible for building the GUI.

Create an interface MessageDecoder that has a single abstract method decode( cipherText), where cipherText is the message to be decoded. The method will return the decoded message. Modify the classes SubstitutionCipher and ShuffleCipher, as described in Exercises 16 and 17, so that they implement MessageDecoder as well as the interface MessageEncoder that Exercise 15 describes. Finally, write a program that allows a user to encode and decode messages entered on the keyboard.

This project demonstrates creating multiple concrete classes that implement two related interfaces. The most difficult part of this implementation is handling characters in the substitution cipher.

The three basic stack operations are push, pop, and first.

Answer the following statement true (T) or false (F)