#7.4.9. 누름 버튼(3개) + 3색 LED 

void setup() {

  pinMode(2, INPUT_PULLUP);

  pinMode(3, INPUT_PULLUP);

  pinMode(4, INPUT_PULLUP);

  pinMode(9, OUTPUT);

  pinMode(10, OUTPUT);

  pinMode(11, OUTPUT);

}

void loop() {

  if (digitalRead(2) == LOW) {

    analogWrite(11, 0);

    analogWrite(10, 0);

    analogWrite(9, 255);

  } else if (digitalRead(3) == LOW) {

    analogWrite(11, 0);

    analogWrite(10, 255);

    analogWrite(9, 0);

  } else if (digitalRead(4) == LOW) {

    analogWrite(11, 255);

    analogWrite(10, 0);

    analogWrite(9, 0);

  } else {

    analogWrite(11, 0);

    analogWrite(10, 0);

    analogWrite(9, 0);

  }

}