text: #ifndef MPAGSCIPHER_CAESARCIPHER_HPP
  #define MPAGSCIPHER_CAESARCIPHER_HPP
  #include <string>
  #include <vector>
  
  class CaesarCipher{
      public:
      explicit CaesarCipher(const std::string& key);
      explicit CaesarCipher(const unsigned long& key);
      const unsigned long key_;
  
    std::string applyCipher (const std::string& inputText, const bool encrypt) const;
    const std::vector<char> alphabet_{{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'O',
    'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'}};
  
    const std::vector<char>::size_type alphabetSize_{alphabet_.size()};
  
  
  
  };
  #endif