public static boolean isLower(char c){
        return c >= 97 && c <= 122;
        }
    public static boolean isUpper(char c){
        return c >= 65 && c <= 90;
        }
   
   
    public static String caesarCipher(String s, int k) {
        String encrypted_text = "";
        int n = s.length();
        
        for(int i = 0; i < n; i++){
            char c = s.charAt(i);
            if(isUpper(c))
                c = (char)( ( ( ( (int)c - 65) + k) % 26) + 65) ;
            else if(isLower(c))
                c = (char)( ( ( ( (int)c - 97) + k) % 26) + 97) ;
            
            
            encrypted_text += c;
            }
        return encrypted_text;

        }