Using Java to solve the problem. Your boss has come to ask for your help with another task. She would like you to write a simple program that encodes and decodes secret messages which she plans to demonstrate to elementary school students to kindle their interest in Computer Science.

The encoding/decoding scheme is very simple. Each letter is substituted by some other letter according to a given mapping as shown below. DO NOT CHANGE THE FOLLOWING STRING

String letters = "abcdefghijklmnopqrstuvwxyz"; String enc = "kngcadsxbvfhjtiumylzqropwe";

For example, every 'a' becomes a 'k' when encoding a text, and every 'k' becomes an 'a' when decoding.

You will write a program, SecretMessage.java, which asks the user whether they would like to encode or decode a message, and then encodes or decodes the message using the mapping above.

Capital letters mapped the same way as the lower case letters above, but remain capitalized.

For example, every 'A' becomes 'K' when encoding a text and every 'K' becomes an 'A' when decoding. Numbers and other characters are not encoded and remain the same. The program repeatedly asks the user for input until the user quits.

Below is one run of the program:

Enter 1 to encode, 2 to decode, 3 to quit: 1 Enter the text to encode:

Santa Monica College Spring 2014 Lktzk Jitbgk Gihhasa Luybts 2014

Enter 1 to encode, 2 to decode, 3 to quit: 1 Enter the text to encode:

programming is fun uyisykjjbts bl dqt

Enter 1 to encode, 2 to decode, 3 to quit: 2 Enter the text to decode:

Lktzk Jitbgk Gihhasa Luybts 2014 Santa Monica College Spring 2014

Enter 1 to encode, 2 to decode, 3 to quit: 3 Good bye

Hints:

Think about decomposing the problem into simpler problems. You will likely find it helpful to

write a few very simple methods first:

• isLowerCaseLetter takes a char and returns true if that letter is a lower case letter (between 'a' and 'z'). isUpperCaseLetter and isLetter should work similarly.
• toLowerCase takes an upper case letter and returns the same letter in lower case. Do not use conditionals to implement this (if/else or switch). Instead, remember that a char is a number code. Print that number code for 'A', 'B', 'a', 'b' to see how it looks and come up with a very simple way to change an upper case letter to lower case. toUpperCase should work similarly.
• codeChar takes a char and a boolean flag. If the flag is true, it returns the encoded char according to the given mapping. If the flag is false, it returns the decoded char according to the given mapping. Do not use conditionals to do the mapping. Instead, notice that the letter 'a' is encoded to the first character of the given encoding map. The letter 'b' to the second,

and so on. For the decoding, you can write a decoding string by hand that you can use to map the encoded letters 'a' to 'z' to their decoded counterparts.

Given a String in Java you can use the charAt method to get the letter at a given position. For example:

String s = "example";

char first = s.charAt(0); // first is assigned 'e'

char second = s.charAt(1); // second is assigned 'x'

Notice that to get the character at the first position we pass the argument 0 to the charAt method and not 1.

• codeMessage takes a String and a boolean flag. If the flag is true, it prints the given message encoded. If the flag is false, it prints the given message decoded. This method just calls the codeChar method for every character in the String and prints the character that codeChar returns. It is really short and simple.

Given a String in Java you can use the length method to get the number of characters in that String. For example:

String s = "hello";

int len = s.length(); // len is assigned 5

Deliverables:

SecretMessage.java

How you lose points:

• If your code does not follow Java coding standards regarding naming of classes, variables, methods, constants, etc.
• If your code is not formatted properly and I find it hard to read.
• If your code is not commented properly:
  • Every class file should have a header comment that includes your name and assignment number and briefly documents what the program does.
  • If there are known deficiencies with your program such as known problems or incomplete features, these should be clearly listed in the header comment.
  • Every method should have a method header comment that documents what the method does, what its parameters are, and what it returns.
  • Every complex block of code should have at least a line comment documenting that code's intent.
• If your source code has print out statements you used for debugging or commented out code you used to try out ideas. Clean up your code before you submit. Do not leave clutter behind.

Your boss has come to ask for your help with another task. She would like you to write a simple program that encodes and decodes "secret messages which she plans to demonstrate to elementary school students to kindle their interest in Computer Science. The encoding/decoding scheme is very simple. Each letter is substituted by some other letter according to a given mapping as shown below. DO NOT CHANGE THE FOLLOWING STRING String letters = "abcdefghijklmnopqrstuvwxyz"; String enc = "kngcadsxbvthjtiumy Izqropwe"; For example, every 'a' becomes a 'k' when encoding a text, and every 'k' becomes an 'a' when decoding. and so on. For the decoding, you can write a decoding string by hand that you can use to map the encoded letters 'a' to 'z' to their decoded counterparts. Given a String in Java you can use the charAt method to get the letter at a given position. For example: String s = "example"; - char first = S.charAt(0); // first is assigned 'e', char second = Schacat(1); // second is assigned 'x', Notice that to get the character at the first position we pass the argument 0 to the charAt method and not 1.. code Message takes a String and a boolean flag. If the flag is true, it prints the given message encoded. If the flag is false, it prints the given message decoded. This method just calls the codeChar method for every character in the String and prints the character that codeChar returns. It is really short and simple. Given a String in Java you can use the length method to get the number of characters in that String. For example: Strings = "hello"; - int len = slength; // len, is assigned 5. You will write a program, Secret Message.java, which asks the user whether they would like to encode or decode a message, and then encodes or decodes the message using the mapping above. / Capital letters mapped the same way as the lower case letters above, but remain capitalized, For example, every 'A' becomes 'K' when encoding a text and every 'K' becomes an 'A'when decoding. Numbers and other characters are not encoded and remain the same. The program repeatedly asks the user for input until the user quits. Below is one run of the program: Deliverables: Secret Message.java Enter 1 to encode, 2 to decode, 3 to quit: 1 Enter the text to encode: - Santa Monica College Spring 2014 Letzk uitbgk Gibhasa Luybts 2014 - Enter 1 to encode, 2 to decode, 3 to quit: 1 Enter the text to encode: - programming is fun uyisyk i jbts bl dat Enter 1 to encode, 2 to decode, 3 to quit: 2 Enter the text to decode: - bktzk Jitbak Gibhasa Luvbts 2014 Santa Monica College Spring 2014 - Enter 1 to encode, 2 to decode, 3 to quit: 3 Good bye : How you lose points: - If your code does not follow Java coding standards regarding naming of classes, variables, methods, constants, etc. - If your code is not formatted properly and I find it hard to read. - If your code is not commented properly: - Every class file should have a header comment that includes your name and assignment number and briefly documents what the program does. - If there are known deficiencies with your program such as known problems or incomplete features, these should be clearly listed in the header comment. - Every method should have a method header comment that documents what the method does, what its parameters are, and what it returns. - Every complex block of code should have at least a line comment documenting that code's intent. - If your source code has print out statements you used for debugging or commented out code you used to try out ideas. Clean up your code before you submit. Do not leave clutter behind. Hints: Think about decomposing the problem into simpler problems. You will likely find it helpful to write a few very simple methods first: - is LowerCaseLetter takes a char and returns true if that letter is a lower case letter (between 'a' and 'z').isUpperCaseLetter and isLetter should work similarly. to LowerCase takes an upper case letter and returns the same letter in lower case. Do not use conditionals to implement this (if/else or switch). Instead, remember that a char is "a number" code. Print that number code for 'A', 'B', 'a', 'b' to see how it looks and come up with a very simple way to change an upper case letter to lower case. to UpperCase should work similarly. codeChar takes a char and a boolean flag. If the flag is true, it returns the encoded char according to the given mapping. If the flag is false, it returns the decoded char according to the given mapping. Do not use conditionals to do the mapping. Instead, notice that the letter 'a' is encoded to the first character of the given encoding map. The letter 'b' to the second