int datapin = 4; 
int clockpin = 3;
int latchpin = 2;

// sketch written by SparkFun Electronics

byte data = 0;

void setup()
{
  // Set the three SPI pins to be outputs:

  pinMode(datapin, OUTPUT);
  pinMode(clockpin, OUTPUT);  
  pinMode(latchpin, OUTPUT);
}

void loop()
{

  // To try the different functions below, uncomment the one
  // you want to run, and comment out the remaining ones to
  // disable them from running.

   binaryCount();        // Bit patterns from 0 to 255
}

void shiftOutput(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val) {
    uint8_t i;

    for(i = 0; i < 8; i++) {
        if(bitOrder == LSBFIRST)
            digitalWrite(dataPin, !!(val & (1 << i)));
        else
            digitalWrite(dataPin, !!(val & (1 << (7 - i))));

        digitalWrite(clockPin, HIGH);
        digitalWrite(clockPin, LOW);
    }
}

void binaryCount()
{
// This function creates a visual representation of the on/off pattern
// of bits in a byte. 

  int delayTime = 200; // time (milliseconds) to pause between LEDs
                        // make this smaller for faster switching

  // Send the data byte to the shift register:

  // shiftOut(datapin, clockpin, MSBFIRST, data);
  shiftOutput(datapin, clockpin, MSBFIRST, 15);

  // Toggle the latch pin to make the data appear at the outputs:

  digitalWrite(latchpin, HIGH);
  digitalWrite(latchpin, LOW);

  // Add one to data, and repeat!
  // (Because a byte type can only store numbers from 0 to 255,
  // if we add more than that, it will "roll around" back to 0
  // and start over).

  data++;

  // Delay so you can see what's going on:

  delay(delayTime);
}