Like my username states, I'm a total newbie with arduino. Basically I short-circuited arduino, and it looks like it has some kind of protection because he immediately started to restart (shutting down and again booting up).
After a while I tested again this setup (yes, I'm that dumb), and this time it didn't restart at all! As this was my input test, i tested digitalRead (to the pin where my button is) and found out that it just went wild. 0 and 1 are changing rapidly.
So my question is: Why didn't it restart the second time I did this mistake. Did I damaged the board or something?
You can test the arduino by uploading the blink code, it will blink the LED on pin 13. If not, it is broken.
In your schematic, you don't actually short circuit the Arduino. However, you are doing it wrong. When you press the button, input 2 is connected to 5V, so digitalRead should return 'high' or 1 or whatever. When you release the button, input 2 is connected to nothing. So what should digitalRead return? Random crap, since it's connected to nothing. The solution is to activate the internal pulldown resistor.
pinMode(2, INPUT); // set pin 2 to input
digitalWrite(pin, LOW); // turn on pullup resistors
This will make sure that the input pin, when nothing is connected (the button is not pressed) is pulled down (to the ground).
If you still experience problems, please also post your code.
Thanks! Luckily it isn't broken, I misunderstood the concept. Thanks for clearing that up for me.