encryptiontemplate.cpp

C++大学简明教程,解压就行没有密码。希望对大家有用

// Exercise 21.12: EncryptionTemplate.cpp
// This application uses a function template to encrypt integer
// and string values.
#include <iostream> // required to perform C++ stream I/O
#include <cmath> // required to use the C++ math library functions
#include <string> // required to access string functions

using namespace std; // for accessing C++ Standard Library members

// function main begins program execution
int main()
{
   // define variables
   int value; // original integer
   int encryptedInteger = 0; // encrypted integer
   string plainText; // string to be encrypted
   int response = 0; // menu selection
   int singleDigit; // the current ones digit of value
   int returnValue; // value returned by encrypt

   // while response does not equal three
   while ( response != 3 )
   {
      // prompt the user for and input menu selection
      cout << "\nPlease select an option" << endl;
      cout << "1 - Encrypt an integer" << endl;
      cout << "2 - Encrypt a string" << endl;
      cout << "3 - Exit the application" << endl;
      cout << "Enter selection: ";
      cin >> response;

      // encrypt an integer value
      if ( response == 1 )
      {
         // prompt the user for an integer value
         cout << "\nEnter an integer value: ";
         cin >> value;

         // encrypt value one digit at a time
         for ( int i = 0; value > 0; i++ )
         {
            // get the next digit of value
            singleDigit = value % 10;

            // encrypt the digit
              
            // shift the returnValue to the correct decimal place
            returnValue *= static_cast< int >( pow( 10.0, i ) );
            
            // add return value to encryptedInteger
            encryptedInteger += returnValue;

            // divide value by 10 to remove encrypted digit
            value /= 10;
         } // end for

         // display the encrypted integer
         cout << "\nThe encrypted integer is: " 
              << encryptedInteger << endl;

         encryptedInteger = 0; // reset encryptedInteger
      } // end if
      else if ( response == 2 ) // encrypt a string
      {
         cin.ignore(); // remove newline from cin

         // prompt the user for a string
         cout << "\nEnter a string: ";
         getline( cin, plainText );

         // display the encrypted string
         cout << "\nThe encrypted string is: ";

         // encrypt plainText one character at a time
         for ( int i = 0; i < plainText.length(); i++ )
         {
         } // end for

         cout << endl; // insert newline for readability
      } // end else if

   } // end while

   cout << endl; // insert newline for readability

   return 0; // indicates that program ended successfully

} // end function main

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