// ------ Reads the state of a switch and lights LEDs accordingly ---
//       -Using variables to store pin numbers
//
//  > Wire an LED from Pin 7 thru 330 ohm resistor to GND
//  > Wire an LED from Pin 6 thru 330 ohm resistor to GND
//  > Wire a switch between Digital Pin 5  and GND
//---------------------------------------------------------------------

boolean buttonState = 0;    // create variable for storing "state" of the button
int LED1 = 7;             // create variable for LED pin number
int LED2 = 6;             // create variable for LED pin number
int buttonPin = 5;          // create variable for button pin number

void setup() {                      // Only do once at startup           
  pinMode(LED1, OUTPUT);            // initialize digital pin as an output (for LED1.)
  pinMode(LED2, OUTPUT);            // initialize digital pin as an output (for LED2.)
  pinMode(buttonPin, INPUT_PULLUP); // initialize digital pin as an input (for switch.)
}
void loop()  {                          // repeat forever  
  buttonState = digitalRead(buttonPin); // "Read" the voltage present on the pin (check switch.)
  
 //-- If the pin wired to the button is low, the switch is closed
  if (buttonState == LOW) {     
    digitalWrite(LED2, LOW);              // turn LED2 off: 
    digitalWrite(LED1, HIGH);             // blink LED1 
    delay(75);
    digitalWrite(LED1, LOW);     
    delay(75);
  } 
   // Otherwise, assume the switch is open.
  else {
    digitalWrite(LED2, HIGH);             // turn LED2 on: 
    digitalWrite(LED1, LOW);              // turn LED off:
  }
}