H  I  J K L    M N O  P  Q R S  T   U  V  W X Y   Z  A   B  C   D  E  F   G
 
A B C D  E   F G H   I   J  K L  M  N  O  P  Q  R  S T  U   V  W  X  Y   Z 
Where H = A. R = K. A=T. G=Z.

string stringl, string2;
string2 = “ “ // making string2 a null string
cout << "Enter string1; ";
getline(cin, string1);
for(i=0; I < string1.Iength()-1; i++)
for(j=i+1; ]< string1.length();j++)
{
if(string1[i] ! =’ ‘ ) // skipping spaces
{
if (string1[i] == string1 [j]) // finding duplicates
string1[j] = ‘*’; // making the duplicate letter a '*'
)// end if
) // end for j
// Removing the *'s, spaces and creating a new string
for(i=0; i < string1.length(); i++)
{
if(string1[i] != '*' && stringi [i] != ' ') // checking for an asterick (*) and a space
string2 += string1[i];
} // end for i
cout <<string2 << endl;

#include <iostream>
#include <cctype>
#include <iomanip>
#include <cmath>
#include <dos.h>      
#include <fstream>
#include <string>
#include <ctime>
#include <conio.h>
#include <windows.h>
 
#define cls system("cls")
#define frz system("pause");
#define yl  system("color 0e");
 
using namespace std;
 
//********************************** Type definitions
void layout();  // declaration of display function
 string ReadFromFile();  // declaration of function to read from files
 string encrypt(string code, string text); // declaration of function to encrypt files
 string decrypt(string code, string text); // declaration of function to decrypt files
 string codeCreation(string string1, char alphabet[26]); // declaration of function create code
 string numericalValue(string s); // find the number value
 
//********************************** Function Prototypes
 
//********************************** Main Function
//declaration of string variables
 string AlphabetCode = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 string converUppercase(string strn1);
 string s1, s3, original, s7 = "ETRERTRHFG";
 string string2;
 string string3;
 
 
 //the main function were everything starts and ends
 int main()
 	{
   	//declaration of the original alphabet
      char alphabet[26] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
      start:
      //initialization of string
      string s2 = ""; // making string2 a null string
 
 
      //get string from user
      cout << "Enter string to create the decryption alphabet code : ";
		cin >> s1;
      cout << '\n';
      original = s1;
 
 
      //convert string to upper case
      s7 = converUppercase(s1);
 
 
      //create encryption code
      s3 = codeCreation(s7, alphabet);
 
 
      //encrypt the file
      s1 = encrypt(s3, s7);
 
      //decrypt the file
      decrypt(s3, s1);
 
      cout << '\n';
 
      //clear the user screen
      clrscr();
 
      //read from files
      ReadFromFile();
 
     //prove user interaction
     layout();
 
     //paused for 3 seconds
     sleep(3);
 
     //allow user to decode a file again
     int choice;
 
     cout << '\n'<< '\n';
     cout << "to decode another file press 2, or 9 to exit" << '\n';
     		cin >> choice;
 
    	switch (choice){
      case 2:
goto start;
 
      case 9:
      			exit (1);
      default:
           cout<<"invalid choice";
 
   }
 
 
 
   	getch();
   	return 0;
 
	}//end main
 
 
 //the folowing is the initialization of the code us in the decrypt function
 string codeCreation(string string1,  char alphabet[26]){
 
     //initialization of string
     string3= "";
   for(int i=0; i < string1.length()-1; i++)
			for(int j=i+1; j< string1.length(); j++)
			{
				if(string1[i] !=' ' ) // skipping spaces
				{
					if (string1[i] == string1[j]) {// finding duplicates
                 // if (string1[j] !='*')
                  //string3 +=  string1[j];
 
                  string1[j] = '*';  }
						// making the duplicate letter a '*'
				}// end if
			} // end for j
         //cout << "string1 = " << string1;
      // Removing the *'s, spaces and creating a new string
		for(int i=0; i < string1.length(); i++)
		{
			if(string1[i] != '*' && string1[i] != ' ') // checking for an asterick (*) and a space
				string2 += string1[i];
         //else
            //string3 += string1[i];
      } // end for i
 
      //check do +
      for(int i=0; i < 26; i++)
		{
         for(int j=0; j < string2.length(); j++)
			  	if(alphabet[i] == string2[j])
                  alphabet[i] = '+';
      } // end for i
 
      //create string3
      for(int i=0; i < 26; i++)
		{
 
			  	if(alphabet[i] != '+')
                  string3 += alphabet[i];
      } // end for i
 
 
        cout << '\n';
     //cout << string1;
        cout << '\n';
        string3 =   string2 + string3;
     //cout << "string 3 = " << string3;
             cout << '\n';
     //cout << "string 2 = " << string2;
     cout << '\n';
 
     return  string3;
     }//end function
 
 
 
     //the following function will encrypt a file
     string encrypt(string code, string text)
     {
                              //cout << '\n';
      //   cout << "your original text is first converted to uppercase to give "
         //			<< "the result below : "<<'\n'<<"Uppercase Original text : "
           //       	<< text<<'\n';
         for(int i=0; i < text.length(); i++)
         {
 
           		if (text[i] == code[0] )
               	text[i] = 'A';
            	else if (text[i] == code[1] )
               	text[i] = 'B';
            	else if (text[i] == code[2] )
               	text[i] = 'C';
            	else if (text[i] == code[3] )
               	text[i] = 'D';
              else if (text[i] == code[4] )
               	text[i] = 'E';
            	else if (text[i] == code[5] )
               	text[i] = 'F';
            	else if (text[i] == code[6] )
               	text[i] = 'G';
            	else if (text[i] == code[7] )
               	text[i] = 'H';
            	else if (text[i] == code[8] )
               	text[i] = 'I';
            	else if (text[i] == code[9] )
               	text[i] = 'J';
            	else if (text[i] == code[10] )
               	text[i] = 'K';
            	else if (text[i] == code[11] )
               	text[i] = 'L';
            	else if (text[i] == code[12] )
               	text[i] = 'M';
            	else if (text[i] == code[13] )
               	text[i] = 'N';
            	else if (text[i] == code[14] )
               	text[i] = 'O';
            	else if (text[i] == code[15] )
               	text[i] = 'P';
            	else if (text[i] == code[16] )
               	text[i] = 'Q';
            	else if (text[i] == code[17] )
               	text[i] = 'R';
            	else if (text[i] == code[18] )
               	text[i] = 'S';
            	else if (text[i] == code[19] )
               	text[i] = 'T';
            	else if (text[i] == code[20] )
               	text[i] = 'U';
            	else if (text[i] == code[21] )
               	text[i] = 'V';
            	else if (text[i] == code[22] )
               	text[i] = 'W';
            	else if (text[i] == code[23] )
               	text[i] = 'X';
            	else if (text[i] == code[24] )
               	text[i] = 'Y';
            	else if (text[i] == code[25] )
               	text[i] = 'Z';
 
         }//END FOR
 
 
        cout << text << " ";
 
 
     		return text;
     }
 
 
 
     //the following function will convert from lower case to uppercase
      string converUppercase(string strn1)
     {
           cout << " ";
 
      	for(int i=0; i < strn1.length(); i++)
           if(strn1[i] == 'a')
              strn1[i] = 'A';
           else if(strn1[i] == 'b')
              strn1[i] = 'B';
           else if(strn1[i] == 'c')
              strn1[i] = 'C';
           else if(strn1[i] == 'd')
              strn1[i] = 'D';
           else if(strn1[i] == 'e')
              strn1[i] = 'E';
           else if(strn1[i] == 'f')
              strn1[i] = 'F';
           else if(strn1[i] == 'g')
              strn1[i] = 'G';
           else if(strn1[i] == 'h')
              strn1[i] = 'H';
           else if(strn1[i] == 'i')
              strn1[i] = 'I';
           else if(strn1[i] == 'j')
              strn1[i] = 'J';
           else if(strn1[i] == 'k')
              strn1[i] = 'K';
           else if(strn1[i] == 'l')
              strn1[i] = 'L';
           else if(strn1[i] == 'm')
              strn1[i] = 'M';
           else if(strn1[i] == 'n')
              strn1[i] = 'N';
           else if(strn1[i] == 'o')
              strn1[i] = 'O';
           else if(strn1[i] == 'p')
              strn1[i] = 'P';
           else if(strn1[i] == 'q')
              strn1[i] = 'Q';
           else if(strn1[i] == 'r')
              strn1[i] = 'R';
           else if(strn1[i] == 's')
              strn1[i] = 'S';
           else if(strn1[i] == 't')
              strn1[i] = 'T';
           else if(strn1[i] == 'u')
              strn1[i] = 'U';
           else if(strn1[i] == 'v')
              strn1[i] = 'V';
           else if(strn1[i] == 'w')
              strn1[i] = 'W';
           else if(strn1[i] == 'x')
              strn1[i] = 'X';
           else if(strn1[i] == 'y')
              strn1[i] = 'Y';
           else if(strn1[i] == 'z')
              strn1[i] = 'Z';
           else
              strn1[i] = strn1[i];
 
   	return strn1;
     }
 
 
     //the following function will decode a file
     string decrypt(string code, string text)
     {
 
     //initialization of string
     string answer = " ";
     int hold = 99, temp = 3;
 
     	        //cout << '\n';
         //cout << "decry befor CODE " << code;
         //cout << '\n';
         //cout << "decrypted text " << text << '\n';
 
 
            // the following is a loop that read all characters from the text input file
     for(int j=0; j < text.length(); j++)
     {
     		//ensure that j is not repeated
     		if(temp == j) {}
 
         else
         // the following is a loop that read all characters from the text input file
       	for(int c=code.length()-1; c >=0 ; c--)
         {
                //cout << temp << " diff temp = " <<  "j " << j << '\n';
         		if(j == temp)
               	cout << temp << " temp = " <<  "j " << j << '\n';
                  //break;//j = temp++;
 
               //start the encryption
                 	if(AlphabetCode[c] == text[j] && hold !=j)
            	{
                  text[j] = code[c];
                  //cout << " j code " << j;
						//cout << "    c code " << c ;
						//cout << "    text code " << code[c] << '\n';
                                          break;
               }
               else
                	//do no changes
               	text[j] = text[j];
 
              hold = temp;
             }  //sleep(1);
 
               //check that j has change
             	if(temp != j){
               temp = j;
                }
                else
                    cout << " same ";
 
               // hold = j;
 
 
            }
 
         //output to screen
         cout << " " << text;
 
         //return string
     		return text;
     }
 
 
 
    //function that reads information from file
     string ReadFromFile(){
 
     //declaration of strings
         string TextFromFile, sConvertToUpper, printToFile, encryptFile;
 
 
         //the following provide interaction will files on the computer
         ofstream outfile ("decodeFile.txt", ios::out);
         ofstream outdecode ("output.txt", ios::out);
      	ifstream inencrypt ("output.txt", ios:: in);
      	ifstream infile ("f1234.txt", ios:: in);
 
         //check if file was open
         if (!infile)
         {
         	cout << "Error opening file"; exit (1);
         }
 
         //check if file was open
         if (!inencrypt)
         {
         	cout << "Error opening file"; exit (1);
         }
 
 
         //check if file was open
         if (!outdecode)
         {
         	cout << "Error opening file for printing"; exit (1);
         }
 
         //check if file was open
         if (!outfile)
         {
         	cout << "Error opening file for printing"; exit (1);
         }
 
 
      //read all from the text file
   	while (infile >>TextFromFile)
        {
 
         //conver each word in the file f1234.txt to uppercase
         sConvertToUpper = converUppercase(TextFromFile);
 
         //encrypt the ininformation read from f1234.txt
         encryptFile = encrypt(s3, sConvertToUpper);
 
         //print the encrypted information to a file called output.txt
        	outdecode <<  encryptFile << " ";
 
         //decrypt the information that was encrypt
         printToFile = decrypt(s3, encryptFile);
 
          //print the decrypt information to a file called decodeFile.txt
         outfile << printToFile << " ";
 
        }
        //cout << TextFromFile << " ";
 
         //conver each word in the file f1234.txt to uppercase
         sConvertToUpper = converUppercase(TextFromFile);
 
         //encrypt the ininformation read from f1234.txt
         encryptFile = encrypt(s3, sConvertToUpper);
 
         //print the encrypted information to a file called output.txt
        	outdecode <<  encryptFile << " ";
 
         //decrypt the information that was encrypt
         printToFile = decrypt(s3, encryptFile);
 
          //print the decrypt information to a file called decodeFile.txt
         outfile << printToFile << " ";
 
      //return the string
      return TextFromFile;
 
     }
 
 
   //the following function provides interaction for the user
	void layout()
   {
 
    //clear the screen
     clrscr();
     cout << '\n';
     clrscr();
 
     //display the headder information
     cout << "****************************************************************************";
     cout << '\n';
     cout << "*******       THIS PROGRAM WILL READ FROM THE FILE f1234.txt         *******";
     cout << '\n';
     cout << "*******                          THEN                                *******";
     cout << '\n';
     cout << "*******            ENCRYPT THE FILE AND PRINT TO output.txt          *******";
     cout << '\n';
     cout << "*******                     THEN FINALLY                             *******";
     cout << '\n';
     cout << "*******    DECRYPT THE ENCRYPTED FILE AND PRINT TO decodeFile.txt    *******";
     cout << '\n';
     cout << "****************************************************************************";
     cout << '\n';
 
     //display the original string of characters you entered tfor code creation
     cout << "your original alphabet text is : " << original;
     cout << '\n'<< '\n'<< '\n' ;
 
     //display the code
     cout << "the decrytion alphabet code is below: ";
     cout << '\n'<< "code : "<< s3 << '\n' ;
 
         //declaration of string variables
         string readFromf1234,readfromoutput, readFromdecodeFile;
 
         //provide interaction with files from the computer
         ifstream readdecodeFile ("decodeFile.txt", ios:: in);
      	ifstream readoutput ("output.txt", ios:: in);
      	ifstream readf1234 ("f1234.txt", ios:: in);
 
         //check if file was open
         if (!readf1234)
         {
         	cout << "Error opening file f1234.txt"; exit (1);
         }
 
         //check if file was open
         if (!readoutput)
         {
         	cout << "Error opening file output.txt"; exit (1);
         }
 
 
         //check if file was open
         if (!readdecodeFile)
         {
         	cout << "Error opening file decodeFile.txt"; exit (1);
         }
 
        //paused for 2 seconds
        sleep(2);
         cout << '\n'<< '\n'<< '\n';
         cout << "the following is a copy of the original file read from the file f1234.txt";
         cout << '\n' << '\n';
 
 
         //read all input from f1234.txt
         while (readf1234 >>readFromf1234)
        {
             cout << readFromf1234 << " ";
        }
             cout << readFromf1234 << " ";
             cout << '\n';
 
 
 
 
        //paused for 2 seconds
         sleep(2);
        	cout << '\n'<< '\n'<< '\n';
         cout << "the following is a copy of the file that was encrypted in the file output.txt";
         cout << '\n'<< '\n';
 
          //read all input from output.txt
         while (readoutput >>readfromoutput)
        {
             cout << readfromoutput << " ";
        }
             cout << readfromoutput << " ";
             cout << '\n';
 
 
 
 
        //paused for 2 seconds
         sleep(2);
        	cout << '\n'<< '\n'<< '\n'<< '\n';
         cout << "the following is a copy of the file that was decoded in the file decodeFile.txt";
         cout << '\n'<< '\n';
 
          //read all input from decodefile.txt
         while (readdecodeFile >>readFromdecodeFile)
        {
             cout << readFromdecodeFile << " ";
        }
             cout << readFromdecodeFile << " ";
             cout << '\n';
 
 
   }//end layout function