Caesar Cipher Problem C++ HackerRank

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

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

Sample Input

11
middle-Outz
2
Sample Output

okffng-Qwvb
Explanation

Original alphabet: abcdefghijklmnopqrstuvwxyz
Alphabet rotated +2: cdefghijklmnopqrstuvwxyzab

• Complete the ‘caesarCipher’ function below.
  *
• The function is expected to return a STRING.
• The function accepts following parameters:
• 1. STRING s
• 2. INTEGER k
  */

string caesarCipher(string s, int k) {
    string str;
    for(int i=0;i<s.length();i++)
    {
        k=k%26;
        for(char ch='a';ch <= 'z';ch++) //97-122
        {
            if(s[i] == ch )
            {
                
                if(s[i] + k > 122 )   /
                {
                    s[i]= s[i] + k - 26;
                    
                }
                else {
                     s[i] = s[i] + k;
                    
                }
                break;
            }
            else if(s[i] == ch-32) 
            {
               
               if(s[i] + k > 90 )   
                {
                    s[i]= s[i] + k - 26; 
                }
                else {
                     
                     s[i] = s[i] + k ; 
                }
                break; 
            }
        }
        
    }
    s[s.length()]='\0';
    return s;
}
int main()
{
    string n_temp;
    getline(cin, n_temp);

    int n = stoi(ltrim(rtrim(n_temp)));

    string s;
    getline(cin, s);

    string k_temp;
    getline(cin, k_temp);

    int k = stoi(ltrim(rtrim(k_temp)));

    string result = caesarCipher(s, k);

    fout << result << "\n";

    fout.close();

    return 0;
}