// External interrupt demo code Nashwan J. Sebi, April 2017
int led = 10;
volatile int output = HIGH;        

void setup() 

{
  pinMode(led,OUTPUT); // initialize digital pin led as an output.
  attachInterrupt(digitalPinToInterrupt(2),greenButton,RISING);  //  function for creating external interrupts at pin2 on Rising (LOW to HIGH)
  attachInterrupt(digitalPinToInterrupt(3),redButton,RISING);  //  function for creating external interrupts at pin3 on Rising (LOW to HIGH)   
Serial.begin(4800);
}

void loop() // loop function empty

  {       
   Serial.println("do anything"); 
  }

void  greenButton() //ISR function excutes when push button at pin 2 is pressed   
{
 output = HIGH;
  digitalWrite(led,output);    
}

void redButton()   //ISR function excutes when push button at pin 3 is pressed                             
{                    
output = LOW;  
digitalWrite(led,output);   
}