C6 — Analogue outputs

int ledPin = 10;                 // define the pin for the LED
int upButtonPin = 6;            // define the pin for the "up" button
int downButtonPin = 7;          // define the pin for the "down" button
int upButtonState = 0;          // create a variable for what the up button is doing
int downButtonState = 0;        // create a variable for what the down button is doing
int brightness = 0;             // create a variable for the brightness of the LED

void setup() {
    pinMode(ledPin, OUTPUT);                // set up the ledPin as an OUTPUT
    pinMode(upButtonPin, INPUT_PULLUP);     // set up the buttonPin as an INPUT_PULLUP
    pinMode(downButtonPin, INPUT_PULLUP);   // set up the buttonPin as an INPUT_PULLUP
}

void loop() {
    upButtonState = digitalRead(upButtonPin);      // read the state of the up pushbutton
    downButtonState = digitalRead(downButtonPin);  // read the state of the down pushbutton
    if (upButtonState == LOW) {            // check if the up pushbutton is pressed.
        brightness = brightness + /* ADD CODE HERE */;         // increase the brightness by 1
    }
    if (downButtonState == LOW) {          // check if the down pushbutton is pressed.
        brightness = brightness - /* ADD CODE HERE */;         // decrease the brightness by 1
    }
    if (brightness > 255) {                 // Don't let brightness get bigger than 255
        brightness = 255;
    }
    if (brightness < 0) {                   // Don't let brightness get smaller than 0
        brightness = 0;
    }
    /* ADD CODE HERE */                      // set the brightness of the LED
    delay(10);                               // wait a little while before checking again
}