The Caesar cipher is a very simple way of creating coded messages. The original cipher, attributed to Julius Caesar, involves shifting every letter in a plaintext message 3 positions further down in the alphabet to get the corresponding ciphertext message. For example, a Q in the plaintext message would be shifted by three postions to become a T in the ciphertext. A plaintext message of "YAK AND ZEBRA" would be transformed to the ciphertext message "BDN DQG CHEUD". Note that letters near the end of the alphabet wrap around to the beginning (e.g. Y + 3 = B). You can, of course, perform a Caesar cipher transformation using other values than 3 for the shift. "YAK AND ZEBRA" with a shift of 4, for example, becomes "CEO ERH DIFVE". In this assignment, you will write a function that implements the Caesar cipher.

Your task

Write a program (Java) that:

Asks the user for an integer (the Caesar shift value) and a string (the plaintext),

Calls a function named caesar (see below for details) to obtain the ciphertext, and

Prints the ciphertext.

Your caesar function should look like this:

caesar(shift, plaintext):

'''Returns ciphertext obtained by transforming every letter

in the plaintext by a Caesar cipher by the specified shift.

Non-letter characters should remain unchanged in the ciphertext.'''

[Your code goes here]

return [something]

A typical session with your completed program might look like this:

prompt>

What is your plaintext? follow the elk

What shift do you want to use? 3

Your ciphertext is: iroorz wkh hon

prompt>