Please follow the instructions of the assignment properly and do what is asked while creating appropriate .h and .cpp files. Need- C++ code with comments + output screenshots Submit in the zip file with appropriate headers and cpp files too/n Instructions for submitting the solution 1. Submit the source code file for every programming assignment like .c file, .java file. 2. If any dataset is used then you need to share all the files with solution in a single zip file. 3. Share the readme file in which you have to include the system specification, required software and the execution instructions. 4. Share the output of the programs. If it is a single program then you can submit the screenshot, if multiple files are included then please share the screen recording. Below are some steps that need to be covered in screen recording. ❖ Show the complete solution according to the instructions. ❖ Need to cover all the compilation steps. Show the complete output of program/project. Show all pass test cases if given in assignment. 5. Always add proper comments in code. If any specific package is used then please mention it in comment./n Around 1550 Blaise de Vigenère, a French diplomat from the court of Henry III of France, developed a new table-based scrambling technique to cipher written language. The technique, also known as chiffre quarré or chiffre indéchiffrable, was considered safe until the middle of the 19th century. The Vigenère Cipher is a polyalphabetic substitution technique based on a mapping table like the one shown below: Q ABCDEFGREUKEN NOPARSTUVWXYN F G H I J G H I J K P Key Letter A B C D E F G H I J K L M N O P Q R S T U V W X Y Z с Ꭰ B C D E F G H I J K L M N O P Q R S TUVWXYZA C D E F G H I J K L M N O P Q R S TUVWXYZAB D E F G H I J K L M N O P Q R S T U V W X Y Z ABC E F G H I J K L M N O P Q R S T UVWXYZABCD K L M N O P Q R S T U V W XYZABCDE L M N O H I J K L M N O P T Q R S T U V W X Y Z ABCDEF Q R S U V W X Y ZABCDEFG H I J K L M N O P Q R S T U V W X Y Z ABCDEFGH I J K L M N O P Q R S T U V W X Y Z ABCDEFGHI J K L M N O P Q R S T U V W X Y Z ABCDEFGHIJ L M N O P Q R S T U V W X Y Z ABCDEFGHIJK L M N O P Q R S T U V W X Y Z ABCDEFGHIJKL M N O P Q R S T U V W X Y Z ABCDEFGHIJKLM O P Q R S T U Т Z V W X Y Z ABCDEFGHIJKLMN P Q R S T U V W X Y Z ABCDEFGHIJKLMNO Q R S T U V W X Y Z ABCDEFGHIJKLMNOP R S T U V W X Y Z ABCDEFGHIJKLMNOPQ STU V W X Y Z ABCDEFGHIJKLMNOPQR T U V W X Y Z ABCDEFGHIJKLMNOPQRS U V W X Y Z ABCDEFGHIJKLMNOPQRST V W X Y Z ABCDEFGHIJKLMNOPQRSTU W X Y Z ABCDEFGHIJKLMNOPQRSTUV X Y Z A B C D E F G H I J K L M N O P Q R S T U V W Y Z A B C D E F G H I J K L M N O P Q R S T U V W X ZA B C D E F G H I J K L M N O P Q R S T U V W X Y A B C D E F G H I J K L M N O P Q R S T U V W X Y Z The Vigenère cipher uses this table together with a keyword to encode a message. To illustrate the use of this encryption method, suppose we wish to scramble the following message (Hamlet 3/1): To be, or not to be: that is the question: using the keyword Relations. First, we notice that the table provides only mappings for upper case characters. But this is not really a problem. The mapping is identical for upper and lower case characters. We just rewrite the keyword to consist of upper case characters only. When encoding a message, we convert each character to an upper case one, perform the corresponding encryption function, and output the result in either upper case or lower case depending on the original spelling. All characters not covered in the Vigenère cipher remain unchanged in the output. No keyword character is consumed in this case! We begin by writing the keyword. We repeat the keyword until all characters of the input text are covered. To derive the encoded text using the mapping table, for each letter in the message, one has to find the intersection of the row given by the corresponding keyword letter and the column given by the message letter itself to pick out the encoded letter. Keyword: Message: Scrambled Message: RE LA TI ONS RE LA TION SR ELA TIONSREL To be, or not to be: that is the question: Lt nf, ia ccm lt nf: ngph bk ytf kdtgmatz: Decoding of an encrypted message is equally straightforward. One writes the keyword plus the decoded message: Keyword: Scrambled Message: Decoded Message: RE LA TI ONS RE LA Lt nf, ia ccm lt nf: To be, or not to be: TION SR ELA TIONSREL nqph bk ytf kdtgmatz: that is the question: This time one uses the keyword letter to pick a row of the table and then traces the row to the column containing the encoded letter. The index of that column is the decoded letter. There are many ways to implement the Vigenère cipher. In this midterm, we use two forward iterators to perform the encoding and decoding of plain English text. The first iterator serves as keyword provider, whereas the second one implements the Vigenère cipher algorithm for both encoding and decoding plain English text. Problem 1 (106 marks) Define a forward iterator, called KeyProvider, that yields a sequence of keyword characters. A suggested specification of class KeyProvider is shown below: #pragma once #include <string> class KeyProvider { private: std::string fKeys; size_t fIndex; std::string preprocessString (const std::string& aString) noexcept; // 18 marks public: }; // 32 marks KeyProvider (const std::string & aKeyword, const std::string& aSource) noexcept; char operator* () const noexcept; // 4 marks KeyProvider & operator++() noexcept; // 4 marks KeyProvider operator++ (int) noexcept; // 10 marks bool operator= (const KeyProvider & aOther) const noexcept; // 10 marks bool operator!= (const KeyProvider & aOther) const noexcept; // 4 marks KeyProvider begin() const noexcept; // 10 marks KeyProvider end () const noexcept; // 10 marks The underlying collection for iterator KeyProvider is the string £Keys. The iterator index is fIndex. The iterator KeyProvider has to compute the underling collection first. You start with the keyword, say "Relations", and populate the string fKeys be repeating the keyword, in upper-case letters, for the length of the message. Keyword: Message: "Relations" "To be, or not to be: that is the question:" "RELATIONSRELATIONSRELATIONSREL" fKeys: or Keyword: Message: fKeys: "Relations" "Be cool" "RELATI" Please note, the length of string *Keys equals the number of letters in the message. Only letters consume keyword characters. To facilitate the initialization of fKeys, the method preprocessString() can be used. This method takes a string and returns a new string that consists only of upper-case letters. For example, preprocessString() applied to "Relations" returns "RELATIONS". Similarly, if applied to "To be, or not to be: that is the question: ", the method preprocessString() returns "TOBEORNOTTOBETHATISTHEQUESTION". The implementation of preprocessString() requires the functions isalpha () and toupper(), both defined in <cctype>. The constructor of KeyProvider, initializes £Keys and fIndex. The iterator has to be positioned onto the first element in the underlying collection. The constructor has to compute the keyword sequence for the input text. As a security feature, the constructor has to end with an assert statement that guarantees that the size of fKeys matches the size of the preprocessed input string. The preprocessed input string may be shorter than aSource. The dereference operator* () returns the keyword character the iterator is positioned on. The prefix operator++ () advances the iterator and returns the updated iterator. The postfix operator++ (int) advances the iterator and returns the old iterator. The equivalence operator== () returns true if this iterator and aother are equal. Equivalence requires the same underlying collection and the same position. The equivalence operator!= () returns true if this iterator and aother are not equal. The method begin () returns a copy of this iterator positioned at the first keyword character. The method end () returns a copy of this iterator positioned after the last keyword character. You may test your implementation of KeyProvider using the following test driver (enable #define P1 in main.cpp). Running the test driver should produce the following output: Test KeyProvider First key sequence: "RELATIONSRELATIONSRELATIONSREL" Second key sequence: "RELATI" Third key sequence: 11 11 done Problem 2 (194 marks) Assume the implementation of KeyProvider is correct. Using KeyProvider, define the forward iterator VigenerForewardIterator that satisfies the suggested specification as shown below: #pragma once #include <string> #include "KeyProvider.h" constexpr size_t CHARACTERS = 26; enum class EVigenereMode { Encode, }; Decode class VigenereForwardIterator { private: EVigenereMode fMode; char fMappingTable [CHARACTERS] [CHARACTERS]; KeyProvider fKeys; std::string fSource; size_t fIndex; char fCurrentChar; // Initialize the mapping table // Row 1: B-A // Row 26: A - Z void initializeTable(); void encodeCurrentChar() noexcept; // 38 marks void decodeCurrentChar () noexcept; // 48 marks public: }; VigenereForwardIterator( const std::string& aKeyword, const std::strings aSource, EvigenereMode aMode = EVigenereMode::Encode) noexcept; // 26 marks char operator* () const noexcept; // 2 marks VigenereForwardIterators operator++ () noexcept; // 14 marks Vigenere ForwardIterator operator++ (int) noexcept; // 10 marks bool operator= (const VigenereForwardIterator& aOther) const noexcept; // 10 marks bool operator!= (const VigenereForwardIterators aOther) const noexcept; // 4 marks VigenereForwardIterator begin() const noexcept; // 30 marks VigenereForwardIterator end () const noexcept; // 10 marks The iterator Vigenere ForwardIterator maintains a cipher mode, a mapping table, a keyword provider (another iterator), the source text, the current position, and the current character the iterator has to return. The constructor has to initialize all member variables with sensible variables. Ideally, all member variables except fMappingTable should be initialized using member initializers. Use initializeTable () as the first statement in the constructor to set up the mapping table. Somebody has already implemented this method: