Question

You've been hired by Encoding Egrets to write a C++ console application that encodes and decodes text. Use a validation loop to prompt for and get from the user a string that is up to ten characters in length. Create value function encodedString that takes the string as input and returns the equivalent encoded string. Start with an empty encoded string. Use a for loop to encode each character of the input string. Use the following algorithm to encode a character and append the encoded character to the encoded string:
● Convert the character to an integer (cast to int).
● Add 17 to the integer value.
● Mod the integer value by 256 to insure its stays within the character range 0-255.
● Convert the integer back to a character (cast back to char).

Create value function decodedString that takes the encoded string as input and returns the equivalent decoded string. It does the reverse of function encodedString. The original string and decoded string should be identical. Use formatted output manipulators (setw, left/right) to print the following rows:
● Input string.
● The encoded string (some characters may be unprintable).
● The decoded string.

And columns:
● A left-justified label.
● A left-justified string.

Declare global constants for the maximum string length (14), the shift value (17), the character boundary (256), and the column widths.

The output should look like this:

Welcome to Encoding Egrets
--------------------------

Enter a string up to 14 characters in length to encode: Snow in November!
Error: the string is longer than 14 characters.

Enter a string up to 14 characters in length to encode: Hello World!

String: Hello World!
Encoded string: Yv}}Ç1hÇâ}u2
Decoded string: Hello World!

End of Encoding Egrets

Do not use this sample input for the final run that is pasted below.

Answer 1

Program code to copy:-

#include <iostream>
#include <iomanip>

using namespace std;

//Declare global constants
const int LEN = 14;
const int SHIFT = 17;
const int BOUND = 256;
const int COL = 20;

//Function Prototypes
string encodedString(string str);
string decodedString(string str);

int main()
{
   string str;
  
   //Printing Heading
   cout << "Welcome to Encoding Egrets" << endl;
   cout << "--------------------------" << endl;
  
   do
   {
       //Prompt and read string from user
       cout << "Enter a string up to 14 characters in length to encode: ";
       getline(cin, str);
      
       //Validating entered string
       if(str.length()>14)
           cout << "Error: the string is longer than 14 characters." << endl;
          
   }while(str.length()>14);
  
  
   //Calling function to encode string
   string encode = encodedString(str);
  
   //Calling function to decode string
   string decode = decodedString(encode);
  
   //Displaying output using formatted output manipulators
   cout << left << setw(COL) << "String:" << left << setw(COL) << str << endl;
   cout << left << setw(COL) << "Encoded string:" << left << setw(COL) << encode <<endl;
   cout << left << setw(COL) << "Decoded string:" << left << setw(COL) << decode <<endl;
  
   cout << "End of Encoding Egrets" <<endl;
  
}

//Function takes the string as input and returns the equivalent encoded string.
string encodedString(string str)
{
   //Creating empty string
   string temp="";
  
   int n;

   for(int i=0; i<str.length(); i++)
   {
       //Convert the character to an integer (cast to int).
       n = (int)str.at(i);
       //Add 17 to the integer value.
       n = n + 17;
       //Mod the integer value by 256 to insure its stays within the character range 0-255.
       n = n % BOUND;
       //Convert the integer back to a character (cast back to char)
       temp = temp + (char)n;
   }
  
   //returns the encoded string
   return temp;
}

//Function takes the encoded string as input and returns the equivalent decoded string.
string decodedString(string str)
{
   //Creating empty string
   string temp="";
  
   int n;
  
   for(int i=0; i<str.length(); i++)
   {
       //Convert the character to an integer (cast to int).
       n = (int)str.at(i);
       //Subtract 17 to the integer value.
       n = n - 17;
       //Mod the integer value by 256 to insure its stays within the character range 0-255.
       n = n % BOUND;
       //Convert the integer back to a character (cast back to char).
       temp = temp + (char)n;
   }
  
   //returns the encoded string
   return temp;
}

Screenshot of output:-