Caesar Cipher.cpp

/*
Julius Caesar protected his confidential information by encrypting it using a cipher. Caesar's cipher shifts each letter by a number of letters. If the shift takes you past the end of the alphabet, just rotate back to the front of the alphabet. In the case of a rotation by 3, w, x, y and z would map to z, a, b and c.

Original alphabet:      abcdefghijklmnopqrstuvwxyz
Alphabet rotated +3:    defghijklmnopqrstuvwxyzabc
For example, the given cleartext  and the alphabet is rotated by . The encrypted string is .

Note: The cipher only encrypts letters; symbols, such as -, remain unencrypted.

Function Description

Complete the caesarCipher function in the editor below. It should return the encrypted string.

caesarCipher has the following parameter(s):

s: a string in cleartext
k: an integer, the alphabet rotation factor
Input Format

The first line contains the integer, , the length of the unencrypted string.
The second line contains the unencrypted string, .
The third line contains , the number of letters to rotate the alphabet by.

Constraints



 is a valid ASCII string without any spaces.

Output Format

For each test case, print the encoded string.

Sample Input

11
middle-Outz
2
Sample Output

okffng-Qwvb
Explanation

Original alphabet:      abcdefghijklmnopqrstuvwxyz
Alphabet rotated +2:    cdefghijklmnopqrstuvwxyzab

m -> o
i -> k
d -> f
d -> f
l -> n
e -> g
-    -
O -> Q
u -> w
t -> v
z -> b
*/

#include <bits/stdc++.h>

using namespace std;

// Complete the caesarCipher function below.
string caesarCipher(string s, int k) {
    //string ans(s.length(),'4');
    char a;
    for(auto &c :s)
    {
        if(isalpha(c))
        { 
          a =isupper(c) ? 'A' : 'a';
          c=(char)a+((c-a)+k)%26;
        }
    }
    return s;
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    int n;
    cin >> n;
    cin.ignore(numeric_limits<streamsize>::max(), '\n');

    string s;
    getline(cin, s);

    int k;
    cin >> k;
    cin.ignore(numeric_limits<streamsize>::max(), '\n');

    string result = caesarCipher(s, k);

    fout << result << "\n";

    fout.close();

    return 0;
}