if結構p6-17

int brightness = 0;

int fade_amount = 5;

int btn_state;

int last_btn_state = LOW;

unsigned long last_debounce_time = 0;

void setup()

{

  Serial.begin(9600);

  pinMode(2, INPUT);

  digitalWrite(10, LOW);

}

void loop()

{

  int reading = digitalRead(2);

  if (reading != last_btn_state)    last_debounce_time = millis();

  if ((millis() - last_debounce_time) > 50)

  {

          if (reading != btn_state)

          {

            btn_state = reading;

            if (btn_state == LOW)  chg_brightness();

          }

          else

          {

            if ((millis() - last_debounce_time) > 1000)

                if (btn_state == LOW)   chg_brightness();

          }

  }

  last_btn_state = reading;

}

void chg_brightness()

{

  brightness = brightness + fade_amount;

  if (brightness > 255)brightness = 255;

  if (brightness < 0)brightness = 0;

  if (brightness == 255 || brightness == 0)fade_amount = -fade_amount;

  analogWrite(10, brightness);

  Serial.println(brightness);

  delay(30);

}