#include <iostream>
#include <cstdlib>

using namespace std;


using std :: cout;
using std :: endl;
void encrypt( char [ ] ); // prototypes of functions used in the code
void decrypt( char * ePtr );
int main( )
{
// create a string to encrypt
char string[ ] = "Omnia mutantur";
cout << "Original string is: " << string << endl;
encrypt( string );
// call to the function encrypt( )
cout << "Encrypted string is: " << string << endl;
decrypt( string );
// call to the function decrypt( )
cout << "Decrypted string is: " << string << endl;
system ("pause");
return 0;
}// main

//encrypt data
void encrypt (char e[] )
{
for( int i=0; e[i] != '\0'; ++i ) ++e[i];
} // encrypt

//decrypt data
void decrypt( char * ePtr ) {
for(; * ePtr != '\0'; ++* ePtr ) --(* ePtr);
}

for (i=0,j=0;i<strlen(string);i++)
{
   string[i]=string[i]^key[j++];
   if(j==strlen(key)) j=0;
}

/*
  Name: Encryptor
  Copyright: 2008, September 17th -- Wednesday
  Author: Danielle
  Date: 18/09/08 02:55
  Description: Program encrypts/decrypts a message stored within a file
*/

#include <iostream>
#include <fstream>
#include <stdio.h> // included specifically for _flushall()

using namespace std;

#include "main.h"

int main()
{
    char *Filename = new char[20];
    int ans;

    while (ans != 4) {
    cout << "1 = Encrypt message to file" << endl
         << "2 = Encrypt file" << endl
         << "3 = Decrypt file" << endl
         << "4 = Quit" << endl << endl
         << "Encrypt or decrypt? ";
    cin >> ans;

    switch (ans) {
           case 1 :
                cout << "Please type a filename to encrypt a MESSAGE to: ";
                cin >> Filename;
                _flushall();

                EncryptMessage(Filename);
                system("PAUSE");
                system("CLS");
                break;

           case 2 :
                cout << "Please type a FILENAME to encrypt: ";
                cin >> Filename;
                _flushall();

                EncryptFile(Filename);
                system("PAUSE");
                system("CLS");
                break;

           case 3 :
                cout << "Please type a FILENAME to decrypt the message: ";
                cin >> Filename;
                _flushall();

                Decrypt(Filename);

                system("PAUSE");
                system("CLS");
                break;

           case 4 :
                delete(Filename);
                exit(0);
                break;

    default : system("CLS"); cout << "Incorrect input entered!" << endl << endl;
    }
}
    cout << endl;
    system("PAUSE");
    system("CLS");
    
    delete(Filename);

    return EXIT_SUCCESS;
}

#ifndef MAIN_H
#define MAIN_H

struct Vars {
       char EncryptFile[20001];  // Encrypt fi)le
       char message[20001];      // Encrypt message
       char Decrypt[20001];      // Decrypt message
       long int Encrypt;         // Encryption-key
       int n;                    // Counter
       } Key;

void EncryptMessage(char *Filename) {

     Key.n = 0;
     ofstream out;

    // Open the file to write to it
    out.open(Filename);

    if (out.fail()) {
    cout << "Couldn't create the file\n\n";
    return;
    }

    cout << "Enter message to encrypt: ";
    cin.getline(Key.message, 20001), '\n';

    cout << "Enter key to encrypt with: ";
    cin >> Key.Encrypt;
    cout << "<<---------------------------->>" << endl << endl;

    // Loop to encrypt message -- XOR
    while (Key.message[Key.n] != '\0') {
          Key.message[Key.n] ^= Key.Encrypt;
          Key.n++;
    }

    out << Key.message;
    out.close();

    // Open the file to write to it
    out.open("Key.txt");

    if (out.fail()) {
    cout << "Couldn't create the file\n\n";
    return;
    }
    
    out << "Filename: " << Filename << endl;
    out << "Encryption key: " << Key.Encrypt << endl;
    out.close();

     return;
}

void Decrypt(char *Filename) {

     Key.n = 0;

     char FileCharacter;
     fstream FileMod;
    
    FileMod.open(Filename, ios_base::in);

    if (!FileMod.is_open()) {
    cout << "\nFile not found.\n\n";
    return;
    }

    cout << "Enter key to decrypt message with: ";
    cin >> Key.Encrypt;
    cout << "<<---------------------------->>" << endl << endl;

     while ( (FileCharacter = FileMod.peek()) != EOF)  {
           FileMod.get(Key.Decrypt[Key.n]);
           Key.n++;
           }

     FileMod.close();

     Key.n = 0;

    // Loop to dencrypt message -- XOR
    while (Key.Decrypt[Key.n] != '\0') {
          Key.Decrypt[Key.n] ^= Key.Encrypt;
          Key.n++;
    }

    cout << Key.Decrypt;
    cout << endl << endl << "<<---------------------------->>" << endl << endl;

     return;
}

void EncryptFile(char *Filename) {

     Key.n = 0;

     char FileCharacter;
     ifstream inFile;
     ofstream outFile;

    inFile.open(Filename, ios_base::in);

    if (!inFile.is_open()) {
    cout << "\nFile not found.\n\n";
    return;
    }

    cout << "Enter key to encrypt FILE with: ";
    cin >> Key.Encrypt;
    cout << "<<---------------------------->>" << endl << endl;

    // Read file into Key.EncryptFile
     while ( (FileCharacter = inFile.peek()) != EOF)  {
           inFile.get(Key.EncryptFile[Key.n]);
           Key.n++;
           }

     inFile.close();

     Key.n = 0;

    // Loop to dencrypt message -- XOR
    while (Key.EncryptFile[Key.n] != '\0') {
          Key.EncryptFile[Key.n] ^= Key.Encrypt;
          Key.n++;
    }

    outFile.open(Filename, ios_base::in);

    if (!outFile.is_open()) {
    cout << "\nFile not created.\n\n";
    return;
    }

    outFile << Key.EncryptFile;
    outFile.close();
/*
    // Open the file to write to it
    outFile.open("Key.txt");

    if (outFile.fail()) {
    cout << "Couldn't create the file\n\n";
    return;
    }
    
    outFile << "Filename: " << Filename << endl;
    outFile << "Encryption key: " << Key.Encrypt << endl;
    outFile.close();
*/
     return;
}

#endif