Update columnar-transposition example

+ Use inheritance to provide base class for key based ciphers

cpp/README.md

@@ -4,6 +4,7 @@
 shaunrd0/klips/cpp/
 ├── algorithms  # Examples of various algorithms written in C++
 ├── cmake       # Example of using cmake to build and organize larger projects
+├── cryptography# Examples of encrypting / decrypting using ciphers in C++
 ├── datastructs # Collection of useful datastructures written in C++
 ├── graphics    # Examples of graphics projects written in C++
 ├── patterns    # Examples of various design patterns written in C++

cpp/cryptography/columnar-transposition/driver.cpp

@@ -27,10 +27,10 @@ int main (const int argc, const char * argv[]) {
 
   // Using example keyword from www.braingle.com
   // + The embedded example there doesn't seem to support numbers in keywords :(
-  CipherData cData("ZEBRAS");
+  Columnar cData("ZEBRAS");
 
-  // Taking user input for keyword using CipherData ctor
-//  CipherData cData;
+  // Taking user input for keyword using Columnar ctor
+//  Columnar cData;
 
   int choice = 0;
   bool exit = false;

cpp/cryptography/columnar-transposition/lib-cipher.cpp

@@ -10,8 +10,9 @@
 
 #include "lib-cipher.hpp"
 
-// Initializes orderVect to determine order columns should be used
-void CipherData::InitOrder(std::string temp)
+KeyData::~KeyData() {}
+
+void Columnar::InitOrder(std::string temp)
 {
   // Create a temp value sorted lexicographically, remove duplicate characters
   // https://en.cppreference.com/w/cpp/string/basic_string/operator_cmp
@@ -32,38 +33,8 @@ void CipherData::InitOrder(std::string temp)
 
 }
 
-// Allows getting keyWord when using CipherData default ctor
-std::string CipherData::GetKey()
+void Columnar::ValidateKeyword(const std::string &message)
 {
-  std::string key;
-  std::cout << "Enter the keyword: ";
-  std::getline(std::cin, key);
-  std::cout << "Keyword entered: \"" << key << "\"\n";
-  return key;
-}
-
-// Transpose a character matrix, using a vector of strings
-void CipherData::Transpose(const std::vector<std::string> &in,
-                           std::vector<std::string> &out)
-{
-  int cols = in[0].size();
-  // JIC some other row is larger than the first
-  for (const auto &row : in) cols = (row.size() > cols) ? row.size() : cols;
-  int rows = in.size();
-
-  out.resize(cols);
-
-  for (int i = 0; i < cols; i++) {
-    for (int j = 0; j < rows; j++) {
-      if (in[j].size() <= i) continue;
-      out[i] += in[j][i];
-    }
-  }
-}
-
-void CipherData::ValidateKeyword(const std::string &message)
-{
-  if (keyWord_.size() < message.size()) return;
   // Pop letters from keyWord until it is < message.size()
   while (keyWord_.size() >= message.size()) keyWord_.pop_back();
   // Do not append order to a previous orderVect; Erase it first
@@ -72,7 +43,25 @@ void CipherData::ValidateKeyword(const std::string &message)
   InitOrder(keyWord_);
 }
 
-std::string CipherData::Encrypt(std::string message)
+void Columnar::Transpose(const std::vector<std::string> &in,
+                         std::vector<std::string> &out)
+{
+  size_t cols = in[0].size();
+  // JIC some other row is larger than the first
+  for (const auto &row : in) cols = (row.size() > cols) ? row.size() : cols;
+  size_t rows = in.size();
+
+  out.resize(cols);
+
+  for (size_t i = 0; i < cols; i++) {
+    for (size_t j = 0; j < rows; j++) {
+      if (in[j].size() <= i) continue;
+      out[i] += in[j][i];
+    }
+  }
+}
+
+std::string Columnar::Encrypt(std::string message)
 {
   // If no message was provided, ask for one
   if (message.empty()) {
@@ -80,7 +69,7 @@ std::string CipherData::Encrypt(std::string message)
     std::getline(std::cin, message);
     std::cout << "Encrypting message \"" << message << "\"\n";
   }
-  ValidateKeyword(message);
+  if (keyWord_.size() >= message.size()) ValidateKeyword(message);
   std::string encryptedMessage;
   std::vector<std::string> rows;
 
@@ -99,7 +88,7 @@ std::string CipherData::Encrypt(std::string message)
   return encryptedMessage;
 }
 
-std::string CipherData::Decrypt(std::string message)
+std::string Columnar::Decrypt(std::string message)
 {
   // If no message was provided, ask for one
   if (message.empty()) {
@@ -107,7 +96,7 @@ std::string CipherData::Decrypt(std::string message)
     std::getline(std::cin, message);
     std::cout << "Decrypting message \"" << message << "\"\n";
   }
-  ValidateKeyword(message);
+  if (keyWord_.size() >= message.size()) ValidateKeyword(message);
   std::string decryptedMessage;
   std::vector<std::string> rows;
 

cpp/cryptography/columnar-transposition/lib-cipher.hpp

@@ -16,37 +16,58 @@
 #include<vector>
 
 /******************************************************************************/
-// CipherData struct to hold data and methods related to encrypting / decrypting
-struct CipherData {
+// KeyData struct to hold data related to key ciphers
+struct KeyData {
+  explicit KeyData(std::string key) : keyWord_(std::move(key)) {};
+  explicit KeyData() : keyWord_(GetKey()) {};
+  // Pure virtual dtor to make abstract class despite no pure virtual members
+  virtual ~KeyData() = 0;
+
+  // Allows getting keyWord when using KeyData default ctor
+  static std::string GetKey()
+  {
+    std::string key;
+    std::cout << "Enter the keyword: ";
+    std::getline(std::cin, key);
+    std::cout << "Keyword entered: \"" << key << "\"\n";
+    return key;
+  }
+
+protected:
+  std::string keyWord_;
+};
+// Definition of pure virtual dtor
+
+/******************************************************************************/
+// Columnar struct to define methods related to columnar transposition
+struct Columnar : KeyData {
   // Can't create this object without providing a keyWord to initialize order
-  explicit CipherData(std::string keyWord) : keyWord_(std::move(keyWord))
+  explicit Columnar(std::string keyWord) : KeyData(std::move(keyWord))
   {
     InitOrder(keyWord_);
   }
-  CipherData() : keyWord_(GetKey()) { InitOrder(keyWord_);}
+  // Inherit call to GetKey() from KeyData default ctor
+  Columnar() { InitOrder(keyWord_);}
 
-  /****************************************************************************/
-  // Member functions
-
-  // Initializes orderVect, pass by value to create local copy of keyWord
+  // Initializes orderVect to determine order columns should be used
   void InitOrder(std::string temp);
 
-  static std::string GetKey();
 
-  static void
-  Transpose(const std::vector<std::string> &in, std::vector<std::string> &out);
+  /****************************************************************************/
+  // Member function definitions
 
-  // Default values for param allows calling with no message
+  void ValidateKeyword(const std::string &message);
+
+  // Transpose a character matrix, using a vector of strings
+  static void Transpose(const std::vector<std::string> &in,
+                        std::vector<std::string> &out);
+
+  // Default parameter allows calling Encrypt() to take message input
   std::string Encrypt(std::string message="");
+  // Default parameter allows calling Decrypt() to take message input
   std::string Decrypt(std::string message="");
 
 private:
-  // Used to make a valid keyword from an invalid keyWord
-  // + Still encrypts / decrypts with whatever the user inputs as keyWord
-  // + But technically the keyword is modified without the user knowing :)
-  void ValidateKeyword(const std::string &message);
-
-  std::string keyWord_;
   std::vector<int> orderVect_;
 };