this is too teach students about button use

simple button code for LED

/*
 http://www.arduino.cc/en/Tutorial/Button
 */
const int buttonPin = 7;     // the number of the pushbutton pin
const int green =  13;      // the number of the LED pin


void setup()
{
  pinMode(green, OUTPUT);      
  pinMode(buttonPin, INPUT);     
}

void loop()
{
  if (digitalRead(buttonPin) == HIGH) 
  {     
    digitalWrite(green, HIGH);  
  } 
  else 
  {
    digitalWrite(green, LOW); 
  }
}