Arduino + Pushbutton

Arduino Code

int buttonPin = 3;
int buttonState = 0;

void setup(){

pinMode(buttonPin, INPUT);
Serial.begin(9600);

}

void loop(){

buttonState = digitalRead(buttonPin);
switch(buttonState){

case HIGH:
Serial.println("off");
break;
case LOW:
Serial.println("on");
break;

}
delay(100);

}