involves writing an encryption program in C++. The program uses the following encryption key: "936712845". The encryption algorithm is to go character by character through the name, converting the letter to upper case, and finding the letter or space in this alphabet string: "ABCDEFGHIJKLMNOPQRSTUVWXYZ ". Find the index position of the letter or space in the alphabet string. If a character in the name is not in the alphabet string, display an error message. If the letter in the name is in an even position (we always start counting with 0 in C++), subtract the key, which is 9 for the first letter, from the index position. If the result is less than 0, add that number to 27, which is the length of the alphabet string. If the letter in the name is in the odd position, add the key, which is 3 for the second letter, to the index position. If the result is >= 27, subtract 27 from that number. The encryption key is 9 digits. Once you have gone through the nine digits on the encryption key, start back at index position 0. Here is some code to help you get started.

#include <iostream>
#include <string>
using namespace std;

const string ENCRYPTION_KEY = "936712845";
const int SIZE_ALPHABET = 27;
void main()
{
string name, newName;
int keyIdx, singleKey, singleChar, alphaKey;
string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ";

// convert char digit to a numeric digit
int singleKey = ((int) ENCRYPTION_KEY[keyIdx]) - 48;


Sample Output from Program:
Enter name (blank to quit): Bob
Encrypted Name: TRW

Enter name (blank to quit): 987sdfsdf
ERROR - Invalid character in name

Enter name (blank to quit): Susan
Encrypted Name: JXMHM

Enter name (blank to quit): Thomas Jefferson
Encrypted Name: KKIT USN OCKKTMV

Enter name (blank to quit): Abraham Lincoln
Encrypted Name: SELHGCEDGRKIHML

Enter name (blank to quit): DeVry University
Encrypted Name: VHPYXBMRDDBXLJRF


So far what I have:


What am I missing? Any help would be appreciated!

What error are you having lol. We are all far to lazy to try to find out what you are doing wrong ourselves so post where your stuck or what errors you are having and we will help lol

no errors. i know this is the right formula (at least im pretty sure) im just not positive how to output the Encrypted name...

I would create a separate function that accepts original character, key, and index and returns the new character.

Treat your input string as an array. Replace each char one by one using this new function. Now you have the new string. cout it.

what's the problem?

im a little lost >.< what would that look like?
thank you

pseudocode:

for i = 0 to name.size:
name[i] = encrypt(name[i], i, key[i modulo key.size])

print name

Basically he means have your name as a cstring (an array of characters) and to loop through its entire length passing the character at each index to a function along with its position and the key and make it return the encrypted character to replace the original one in the cstring. After you can just cout or printf the string

im still lost....



What am I doing wrong?

have you tested your singleChar function? what does it print out for each input?