/*
Author: Francesco Taurisano
This algorithm uses the Caesar's cipher method to decrypt a ciphertext file and create a plaintex file.
The secret key is read from the keyboard.
*/
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
   char letter;
   int key;
   cout<<"Insert the secret key ";
   cin>>key;
   ifstream ciphertext("c:/file2.txt");
   ofstream plaintext("c:/file3.txt");
   while(ciphertext.get(letter))
   {
     plaintext.put(letter-key);                       
   }
   ciphertext.close();     
   plaintext.close();
   system("pause");
   return 0;
}