Rotary encoder with push button

#define CLK 2
#define DT 3
#define SW 4

int currentStateCLK;
int lastStateCLK;
int counter = 0;

String currentDir ="";
unsigned long lastButtonPress = 0;

void setup()
     {
          pinMode(CLK,INPUT);
          pinMode(DT,INPUT);
          pinMode(SW, INPUT_PULLUP);
          Serial.begin(9600);
          lastStateCLK = digitalRead(CLK);
        Serial.print("Direction: ");
          Serial.print(currentDir);
          Serial.println(counter);
     }

void loop()
     {
            currentStateCLK = digitalRead(CLK);
          if (currentStateCLK != lastStateCLK  && currentStateCLK == 1)
           {
              if (digitalRead(DT) != currentStateCLK)
                 {
                          counter = counter + 1;
                    if (counter > 100)
                       {
                         counter = 0;
                       }
                          currentDir ="UP";
                     } else
                      {
                                counter = counter - 1;
                          if (counter < 0)
                             {
                                counter = 100;
                             }
                          currentDir ="DOWN";
                          }
                  Serial.print("Direction: ");
                  Serial.print(currentDir);
                  Serial.print(" - Counter: ");
                  Serial.println(counter);
            }

  lastStateCLK = currentStateCLK;
  int btnState = digitalRead(SW);
    if (btnState == LOW)
        {
               if (millis() - lastButtonPress > 50)
              {
                       Serial.println("Button pressed!");
                  }
               lastButtonPress = millis();
          }
    delay(1);
    }