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

uint16_t data = 0;

void setup()
{
  pinMode(datapin, OUTPUT);
  pinMode(clockpin, OUTPUT);
  pinMode(latchpin, OUTPUT);
}


void loop()
{
  oneOnAtATime();       // Scroll down the line
}


void shiftWrite(int desiredPin, boolean desiredState)
{
  digitalWrite(latchpin, LOW);

  if(desiredState)
    data |= (1<<desiredPin);
  else
    data &= ~(1<<desiredPin);

  shiftOut(datapin, clockpin, MSBFIRST, data>>8);
  shiftOut(datapin, clockpin, MSBFIRST, data);

  digitalWrite(latchpin, HIGH);
}



void oneOnAtATime()
{
  int i;
  int delayTime = 1000;
  int myArray[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
  for(i=0; i<16; i++)
  {
    shiftWrite(myArray[i], HIGH);   // turn LED on
    delay(delayTime);       // pause to slow down the sequence
    shiftWrite(myArray[i], LOW);// turn LED off
  }
}