Question

Write a psuedocode for this program.

#include <iostream>

using namespace std;

string message;

string mappedKey;

void messageAndKey(){

string msg;

cout << "Enter message: ";

getline(cin, msg);

cin.ignore();

//message to uppercase

for(int i = 0; i < msg.length(); i++){

msg[i] = toupper(msg[i]);

}

string key;

cout << "Enter key: ";

getline(cin, key);

cin.ignore();

//key to uppercase

for(int i = 0; i < key.length(); i++){

key[i] = toupper(key[i]);

}

//mapping key to message

string keyMap = "";

for (int i = 0,j = 0; i <msg.length();i++){

if(msg[i] ==32){

keyMap += 32;

} else {

if(j<key.length()){

keyMap += key[j];

j++;

} else {

j = 0;

keyMap += key[j];

j++;

}

} //if-else

} //for

message = msg;

mappedKey = keyMap;

}

int vTable[26][26];

void visibleTable(){

for (int i = 0; i < 26; i++){

for (int j = 0; j < 26; j++){

int temp;

if((i+65)+j > 90){

temp = ((i+65)+j) - 26;

vTable[i][j] = temp;

} else {

temp = (i+65)+j;

vTable[i][j] = temp;

}

}

}

for(int i = 0; i <26; i++){

for(int j = 0; j < 26; j++){

cout << (char)vTable[i][j] << " ";

}

cout << endl;

}

}

int tableArr[26][26];

void createVigenereTable(){

for (int i = 0; i < 26; i++){

for (int j = 0; j < 26; j++){

int temp;

if((i+65)+j > 90){

temp = ((i+65)+j) - 26;

tableArr[i][j] = temp;

} else {

temp = (i+65)+j;

tableArr[i][j] = temp;

}

}

}

}

void cipherEncryption(string message, string mappedKey){

createVigenereTable();

string encryptedText = "";

for(int i = 0; i < message.length(); i++){

if(message[i] == 32 && mappedKey[i] == 32){

encryptedText += " ";

} else {

int x = (int)message[i]-65;

int y = (int)mappedKey[i]-65;

encryptedText += (char)tableArr[x][y];

}

}

cout << "Encrypted Text: " << encryptedText;

cout << "\nRestart the program for more encryption or decryption.";

}

int itrCount(int key, int msg){

int counter = 0;

string result = "";

for(int i = 0; i < 26; i++){

if(key+i > 90){

result += (char)(key+(i-26));

} else {

result += (char)(key+i);

}

} //for

for(int i = 0; i < result.length(); i++){

if(result[i] == msg){

break;

} else {

counter++;

}

}

return counter;

}

void cipherDecryption(string message, string mappedKey){

string decryptedText = "";

for(int i = 0; i < message.length(); i++){

if(message[i] == 32 && mappedKey[i] == 32){

decryptedText += " ";

} else {

int temp = itrCount((int)mappedKey[i], (int)message[i]);

decryptedText += (char)(65+temp);

}

}

cout << "Decrypted Text: " << decryptedText;

cout << "Please restart the program for more encryption or decryption.";

}

int main()

{

int choice;

cout << "*****************************************************************************\n ";

cout << "This program encrypts or decrypts messages. \n Press 1 to encrypt, 2 to decrypt or 3 to see the table. \n When inputs are entered, press ENTER two times to procceed.";

cout << "*****************************************************************************\n";

cin >> choice;

cin.ignore();

if (choice == 1)

{

cout << "Encryption was chosen. \n" << endl;

messageAndKey();

cipherEncryption(message, mappedKey);

} else if (choice == 2)

{

cout << "Decryption was chosen. \n" << endl;

messageAndKey();

cipherDecryption(message, mappedKey);

}

else if (choice ==3 )

{

cout << "The table has been chosen. \n Please press 3 to confirm.";

cin >> choice;

if (choice == 3)

{

visibleTable();

}

}

else {

cout << "Wrong Choice. \n Please restart the program" << endl;

}

return 0;

}

Answer 1

The pseudo code for the program is given below.

In case of any query please contact me in comments.

// Pseudo code below

The following program lets you encrypt and decrypt using the key provided

1. function messageAndKey()
{
1.prompt user to input the message in message and
   then covert the input message in uppercase and
   then store it in message array letter by letter.

2.prompt user to input the key in key variable and
   then covert the input key in uppercase and
   then store it in key array letter by letter.

3.next step is to map key to message
   Loop until one loop variable is less than message.length()
       inside loop
       if letter of message array at index i equal to 32
           then add 32 to keymap variable.
       else
           if second loop variable j is less than key.length()
               add key to keymap
           else
               make second variable j equal to 0 and add key to key map
           increment j
       increment i
       end loop

4. Store message and mapped key i some variable
end
}

2.Create a 2-d array

3.function visibleTable()
{
   loop till variable i less than 26
       inner loop run till j less than 26
           if i+65+j is greater than 90
               store i+65+j-26 in a temporary variable
           else
               store i+65+j in temporary variable
           end if
           store the value of temporary variable in the 2-d array at i,j position.
       end for
   end for
  
   print the 2-D array in form of matrix
   loop till variable i less than 26
       inner loop run till j less than 26
           print 2-D array value at i,j
       end for
   end for
end
}

4.Create a 2-d array

5. function createVigenereTable(){
   loop till variable i less than 26
       inner loop run till j less than 26
           if i+65+j is greater than 90
               store i+65+j-26 in a temporary variable
           else
               store i+65+j in temporary variable
           end if
           store the value of temporary variable in the new 2-d array at i,j position.
       end for
   end for
end
}

6. function cipherEncryption(argument one , argument two)
{
   call function createVigenereTable()
   loop till i is less than message.length()
       if value of argument one at i is equal to 32 and value of argument two at i is 32
           add " " to encrypted text variable.
       else
           store value of argument one in variable x after subtracting 65
           store value of argument two in variable y after subtracting 65
           add value of second 2-D array at x,y to encrypted text.
       end if
   end for
   print out the encrypted text.
end
}

6. function itrCount(argument one,argument two) to count number of iterations.
{
   loop till i is less than 26
       if argument one + i is greater than 90
           add argument one + i -26 to result variable
       else
           add argument one + i to result variable.
       end if
   end for
  
   loop till i is less than result.length()
       if value of result at i is equal to argument two
           then break
       else
           increment counter variable
       end if
   end for
   return counter variable
end
}

7.function cipherDecryption(argument one argument two){
   loop till i is less than argument one length
       if value of argument one at i is equal to 32 and value of argument two at i is equal to 32
           add " " to decryptedText variable
       else
           call and store function itrCount(for argument two at i, argument one at i) value in temp variable
           add 65 + temp variable to decrypted text.
       end if
   end for
   print the decrypted text
end
}

8.{In the main function
   print out the menu where user can choose from various options i.e. 1. for encrypt
       2. for decrypt 3. to see table and instructions to use.
   take user choice
   if user chooses 1 to encrypt
       then call function messageAndKey()
       call function cipherEncryption() with appropriate arguments
   else
   if user chooses option 2 to decrpypt
       then call messageAndKey() function
       then call cipherDecryption() function with appropriate arguments
   else
   if user chooses option 3
       then prompt user to confirm
       then if user confirms call visibleTable() function
   else
       ask user to enter correct choice
   end if
end
}

Screenshots