here is my simple C++ solution // // //

string caesarCipher(string s, int k) { string res(""); int ch = 0;

for (auto c : s)
{
    if (isalpha(c))
    {
        int ch = int(c);
        ch += k;

        /* check where we are in relation to 1 -26 , taking into
        account of any Caps letter
        */
        int curr_index = isupper(c) ? (int(c) -65) : int(c) - 97;

        /* by how much are we going to be out of bound*/
        bool out_of_boundOffset = (k + curr_index > 25);

        if ( out_of_boundOffset )
            ch = isupper(c) ? (65 + (k + curr_index) % 26) : (97 + (k + curr_index) % 26);

        res.push_back(char(ch));
    }
    else {
        res.push_back(c);
    }
}
return res;

}