string caesarCipher(string s, int k) {
    string alphabets = "abcdefghijklmnopqrstuvwxyz" ;
    for(int i=0;i<s.length();i++){
        char c = tolower(s[i]);
        int pos = alphabets.find(c);
        if(pos == -1){
            continue;
        }
        if(isupper(s[i])){
            char newChar = alphabets[(pos+k)%26];
            s[i] = toupper(newChar);
        }else{
            s[i] = alphabets[(pos+k)%26];
        }; 
    }
    return s;
}