Raspberry Pi test program using wiringPi; changes blinking rate with button press

buttonLED.c

/*
 * buttonLED.c:
 *      Simple test program to change the blinking rate of an LED when a button is pressed
 */

#include <wiringPi.h>
#include <stdio.h>

int main (void)
{
  int pin_LED = 7;    // GPIO7 / header pin 7
  int pin_switch = 8; // SDA0 / header pin 3
  int del = 250;

  printf ("Raspberry Pi wiringPi button LED test\n") ;

  if (wiringPiSetup() == -1)
    exit (1);

  pinMode(pin_LED, OUTPUT);
  pinMode(pin_switch, INPUT);

  for (;;){
    if (digitalRead (8) == 0){ // button pressed
      del = 100;
    } else {
      del = 250;
    }

    digitalWrite(pin_LED, 1);
    delay(del);
    digitalWrite(pin_LED, 0);
    delay(del);
  }

  return 0 ;
}