Arduino example: LED toggle button

gistfile1.txt

void setup()
{
    pinMode(12, OUTPUT);
    pinMode(2, INPUT_PULLUP);
}

int button;
int last_button;
int led = LOW;
void loop()
{
    last_button = button;
    button = digitalRead(2);
    if (button == LOW && last_button == HIGH)
    {
        led = !led;
    }
    digitalWrite(12, led);
}