C++ 链表凯撒密码 Vigenere Cipher

Posted 2023-02-16

【中文标题】C++ 链表凯撒密码 Vigenere Cipher

【英文标题】：C++ Linked List Caesar Cipher Vigenere Cipher

【发布时间】：2016-11-30 20:17:59

【问题描述】：

我无法让此代码正常工作。我不清楚如何使用链表来实现凯撒密码和维吉纳密码。任何解决此问题的帮助将不胜感激。 该程序应该接受用户的菜单选择。用户将使用创建链接列表的字符字符串填充列表。密码应该比较链表中的每个元素并根据输入的密钥进行加密/解密。

#include <iostream>
using namespace std;
#include <string>

#undef NULL
const int NULL = 0;
const string ELEMENT_NAME = "whole number";
typedef int element;
const char SENTINEL = '\n';
class listnode 
        public:
                element data;
                listnode * next;
        ; 
class LList 
        private:
                listnode * head;
                listnode * tail;
        public:
                LList();
               ~LList();
                void Print();
                void InsertHead(element thing);
                void InsertTail(element thing);
                element DeleteHead();
                void ReadForward();
                void ReadBackward();
                void Clean();
                void Steal(LList & Victim);
                void Duplicate(LList & Source);
                void Reverse();
                void displayMenu();
                char userval;
                void CaesarEncryption(element CaesarKey);
                void CaesarDecryption(element CaesarKey);
                void VigenereEncryption(char VigenereKey);
                void VigenereDecryption(char VigenereKey);
                char EncryptedMessage;
                char DecryptedMessage;
 void Display();
        ;
element read_element();

// Main function
int main()
        // Declare the Ceaser key
        element CaesarKey;

        //Declare the Vigenere key
        char VigenereKey;

       // Declare menu_choice
       char menu_choice;
       LList L;
       do 
                L.Display();

                // Display the menu
                L.displayMenu();

                // Prompt the user to enter their menu selection
                cout << "Please make your menu selection: " << endl;
                cin >> menu_choice;

                // Use validation techniques to make sure the user    enters a
               //valid menu choice
                while((menu_choice != 'h')&&(menu_choice != 'c')&&
                (menu_choice != 'C')&&(menu_choice != 'v')&& (menu_choice!= 'V')&&(menu_choice != 'q')&&(menu_choice != 'm')) 
                        cout << "Error Invalid Choice. Re-enter:";
                        cin >> menu_choice;
                
                switch(menu_choice) 
                        case 'h' :
                                L.displayMenu();
                        break;
                        case 'm' :

                               // Read the message from the user
                                L.ReadForward();
                        break;
                        case 'c':

                                // Prompt the user
                                cout << "Enter the numeric key" ;

                                // Get the user to enter the key
                                CaesarKey = read_element();

                                // encrypt using ceaser cipher
                                L.CaesarEncryption(CaesarKey);

                                //display the current message
                                cout << "The current key is " << CaesarKey;
                                cout << "." << endl;
                        break;
                        case 'C':

                                // prompt the user
                                cout << "Enter the numeric key: ";

                                // Get the user to enter the key
                                CaesarKey = read_element();

                                // decrypt using ceaser cipher
                                L.CaesarDecryption(CaesarKey);
                                cout << "The current key is " << CaesarKey;
                                cout << "." << endl;
                        break;
                        case 'v':

                                // Prompt the user
                                cout << "Enter the key: ";
                                // Get the user to enter the key
                                VigenereKey = cin.get();

                                //encrypt using vigenere cipher
                                L.VigenereEncryption(VigenereKey);

                                //display the key
                                cout << "The current key is " << VigenereKey;
                                cout << "." << endl;

                        break;
                        case 'V':

                                // Prompt the user
                                cout << "Please enter the key: ";

                                //Get the user to enter the Vigenere key
                                VigenereKey = cin.get();

                                // decrypt using vigenere cipher
                                L.VigenereDecryption(VigenereKey);

                                //display the key
                                cout << "The current key is " << VigenereKey;
                                cout << "." << endl;
                        break;
                        case 'q' :

                                // Tell the user they are exiting the program
                                cout << "You are quitting the program." ;
                        break;
                        default:
                                ;
                        break;
                
        while(menu_choice != 'q');
    return 0;


LList :: LList() 
        // PRE: NONE
        // POST: the N.O. LList is valid and empty
        head = NULL;


LList :: ~LList() 
          // PRE: the N.O. LList is valud
         // POST: the N.O. LList is valid and empty, and its
        //      listnodes have been deleted
        Clean();
 

void LList :: Print() 
         // PRE: the N.O. LList is valid
         // POST: the N.O. LList is unchanged and its
        //      elements have been displayed
        listnode * temp;
        temp = head;
        while( temp != NULL) 
                cout << temp -> data << endl;
                temp = temp -> next;
        


void LList :: InsertHead(element thing) 
        // PRE : the N.O. LList is valid
        // POST : the N.O. LList is unchanged, except that a
        //      new listnode containing element thing
        //      has been inserted at the head of the list
        listnode * temp;
        temp = new listnode;
        temp -> data = thing;
        temp -> next = head;
        temp -> next = head;
        if(head == NULL)
                tail = temp;
        else
                ;
        head = temp;


void LList :: InsertTail(element thing) 
        // PRE : the N.O. LList is valid
        // POST : the N.O. LList is unchanged, except that a
        //      new listnode containing element thing has been
        //      inserted at the tail end of the list

        listnode * temp;

        temp = new listnode;
        temp -> data = thing;
        temp -> next = NULL;
        if(head == NULL)
                head = temp;
        else
                tail -> next = temp;
        tail = temp;


element LList :: DeleteHead() 
        // PRE: the N.O. LList is valid and not empty
        // POST: the N.O. LList is unchanged, except that
        //      the listnode at the head end of the list has
        //      been deleted and its data element has
        //      been returned

        listnode * temp;
        element thing;

        temp = head;
        head = head -> next;
        thing = temp -> data;
        delete temp;
        return thing;


void LList :: ReadForward() 
        // PRE: the N.O. LList is valid
        // POST : the N.O. LList is valid, all of its
        //      previous listnodes have been deleted, and
        //      it now consists of new listnodes containing
        //      elements given by the user in foward order

        Clean();
        cout <<  "Enter the message: ";
        userval = cin.get();
        while (cin.get() != SENTINEL) 
                InsertTail(userval);
                userval = cin.get();
        

 

 void LList :: ReadBackward() 
        // PRE: The N.O. LList is valid
        // POST: the N.O. LList is valid, all of its
        //      previous listnodes have been deleted,
        //      and it now consists of new listnodes
        //      containg elements given by the user
        // in backwards order

        element userval;

        Clean();
        cout << "Enter the elements: ";
        userval = read_element();
        while (userval != SENTINEL) 
                InsertHead(userval);
                userval = read_element();
        



void LList :: Clean() 
        // PRE: the N.O. LList is valid
        // POST:: the N.O. LList is valid and empty, and all of its
        //      listnodes have been deleted
        while( head != NULL)
                DeleteHead();


void LList :: Steal(LList & Victim) 
        // PRE: the N.O. and Victim LLists are valid
        // POST : the Victim LList is valid and empty the N.O. LList
        //      is valid, all of its previous listnodes have been
        //      deleted, and it now consists of the listnodes originally
        //      on the Victim LList

        Clean();
        head = Victim.head;
        tail = Victim.tail;
        Victim.head = NULL;


void LList :: Duplicate(LList & Source) 
        // PRE: the N.O. LList and Source LLists are valid
        // POST :: the Source LList is unchanged
        //      the N.O. LList is valid, all of its previous listnodes
        //      have been deleted, and it now consists of listnodes
        //      containing the same elements and in the same order as on
        //      the Source LList

        listnode * temp;

        temp = Source.head;
        while (temp != NULL) 
                InsertTail(temp -> data);
                temp = temp -> next;
        


void LList :: Reverse() 
         // PRE: the N.O. LList is valid
         // POST: the N.O. LList is unchanged, excepts its elements are in
        //      reverse order

        listnode * temp;
        LList Helper;

        temp = head;
        while(temp != NULL) 
                Helper.InsertHead(temp -> data);
                temp = temp -> next;
        
        Steal(Helper);


element read_element() 
        element userval;
        cin >> userval;
        while(!cin.good()) 
                cin.clear();
                cin.ignore(80, '\n');
                cout << "Invalid data type, should be an element ( ";
                cout  << ELEMENT_NAME << " ), try agian. " << endl;
                cin >> userval;
        
        return userval;

void LList :: displayMenu() 
        // PRE: none
        // POST: the menu is displayed for the user along with the current
        userval = ' ';
        EncryptedMessage = ' ';
        DecryptedMessage = ' ';
        cout << "------------------------------------------------------------";
        cout << endl;
        cout << "Command (h for help): h" << endl;
        cout << "m : enter a new current message from the keyboard" << endl;
        cout << "c : encrypt the current message using the Caesar Cipher";
        cout << endl;
        cout << "C : decrypt the current message using the Caesar Cipher";
        cout << endl;
        cout << "v : encrypt the current message using the Vigenere Cipher";
        cout << endl;
        cout << "V : decrypt the current message using the Vigenere Cipher";
        cout << endl;
        cout << "h : show the help menu" << endl;
        cout << "q : quit the program" << endl;

void LList :: CaesarEncryption(element CaesarKey) 
        //PRE:
        // POST:
        int num;
        num = userval;
        for(int x = 0;  x < num; x++)
                if(userval >= 'A' && userval <='Z') 
                    EncryptedMessage=(char)(((userval+CaesarKey-'A'+26)%26)+'A');
                
                else if(userval >= 'a' && userval <= 'z') 
                    EncryptedMessage=(char)(((userval+CaesarKey-'a'+26)% 26)+'a');
                
                else
                        ;
        
        cout << "-------------------------------------------------------"<<endl;
        cout << "The encrypted message is " << EncryptedMessage << "."<<endl;

void LList:: CaesarDecryption(element CaesarKey) 
        //PRE:
        //POST:
        int num;
        num = userval;
        for(int x = 0; x < num; x++) 
                if(userval >= 'A' && userval <= 'Z') 
                        DecryptedMessage = (char)(((userval  - CaesarKey + 26) % 26) + 'A');
                
                else if(userval >= 'a' && userval <= 'z') 
                        DecryptedMessage = (char)(((userval -CaesarKey + 26)% 26) + 'a');
                
                else
                        ;
        
        cout << "-------------------------------------------------------"<<endl;
        cout << "The decrypted message is  '"<< DecryptedMessage << "'."<<endl;

void LList :: VigenereEncryption(char VigenereKey) 
        //PRE:
        //POST:
        unsigned int j = 0;
        for(int x = 0; x < userval; x++) 
                if(isalpha(x)) 
                EncryptedMessage += VigenereKey;
                        if(userval > 'Z')
                                EncryptedMessage += 'Z' + 'A' - 1;
                        else
                                ;
                
                else
                        ;
        

        cout << "-------------------------------------------------------"<<endl;
        cout << "The encrypted message is '" << EncryptedMessage << "'."<<endl;

void LList :: VigenereDecryption(char VigenereKey) 
        // PRE:
        //POST:
        int num;
        num = userval;
        for(int x = 0; x < num; x++) 
                if(isalpha(x))
                DecryptedMessage = (userval - VigenereKey % 26);
        

        cout << "------------------------------------------------------"<<endl;
        cout << "The decrypted message is \"" <<DecryptedMessage << "\"."<<endl;


void LList :: Display() 
        //PRE
        //POST
        cout << "--------------------------------------------------"<<endl;
        if(userval = ' ')
                cout << "The current message is  \"\". " << endl;
         else 
                cout << "The current message is \"" << userval << "\"." << endl;
                cout << "----------------------------------------------------";
                cout << endl;
        

【问题讨论】：

有什么问题？

这段代码实在是太大了。您应该创建一个minimal reproducible example，以便让更多人帮助您。

【参考方案1】：

#include <iostream>
#include<string>
using namespace std;``
int main() 
  string alphapet, plaintext, cipher;
  int option, key;
  alphapet = "abcdefghijklmnopqrstuvwxyz";
  cipher = "xyzabcdefghijklmnopqrstuvw";
  cout << "choose an option atbash cioher : \n 1)to Cipher \n 2)to Decipher \n";
  cin >> option;
  cout << "enter key \n";
  cin >> key;

  cin.ignore();
  char letter;
  if (option == 1 && (key == 3)) 
    cout << "enter the plaintext to cipher :\n ";
    getline(cin, plaintext);
    for (int i = 0; i < plaintext.size(); ++i) 
      for (int j = 0; j < 26; ++j) 
        if (plaintext[i] == alphapet[j]) 
          plaintext[i] = cipher[j];
          break;
        
      
    

  
  if (option == 2) 
    cout << "rnter the plaintext to decipher : \n";
    getline(cin, plaintext);
    for (int i = 0; i < plaintext.size(); ++i) 
      for (int j = 0; j < 26; j++) 
        if (plaintext[i] == cipher[j]) 
          plaintext[i] = alphapet[j];
          break;
        
      
    
  
  cout << plaintext;
  return 0;

【讨论】：

您能否提供一个简短的解释以及您的代码？