Arduino code for counting 1 to 15 in binary using LED light

Using Condition

int lights[] = {8, 9, 10, 11};
int maxNumber = 15;
int numOfLight = sizeof(lights)/sizeof(int);

void setup() {
  // put your setup code here, to run once:
  for (int i = 0; i < numOfLight ; i++) {
    pinMode(lights[i], OUTPUT);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  // represent 0 to 15 with light ->
  for (int i = 1; i <= maxNumber; i++) {
    // for all lights
    for (int j = 0; j < numOfLight ; j++) {
      digitalWrite(lights[j], LOW);

      if (i == 1) {
        digitalWrite(lights[0], HIGH);
      }
      if (i == 2) {
        digitalWrite(lights[1], HIGH);
      }
      if (i == 3) {
        digitalWrite(lights[0], HIGH);
        digitalWrite(lights[1], HIGH);
      }
      if (i == 4) {
        digitalWrite(lights[2], HIGH);
      }
      if (i == 5) {
        digitalWrite(lights[0], HIGH);
        digitalWrite(lights[2], HIGH);
      }
      if (i == 6) {
        digitalWrite(lights[1], HIGH);
        digitalWrite(lights[2], HIGH);
      }
      if (i == 7) {
        digitalWrite(lights[0], HIGH);
        digitalWrite(lights[1], HIGH);
        digitalWrite(lights[2], HIGH);
      }
      if (i == 8) {
        digitalWrite(lights[3], HIGH);

      }
      if (i == 9) {
        digitalWrite(lights[0], HIGH);
        digitalWrite(lights[3], HIGH);
      }
      if (i == 10) {
        digitalWrite(lights[1], HIGH);
        digitalWrite(lights[3], HIGH);
      }
      if (i == 11) {
        digitalWrite(lights[0], HIGH);
        digitalWrite(lights[1], HIGH);
        digitalWrite(lights[3], HIGH);
      }
      if (i == 12) {
        digitalWrite(lights[2], HIGH);
        digitalWrite(lights[3], HIGH);

      }
      if (i == 13) {
        digitalWrite(lights[0], HIGH);
        digitalWrite(lights[2], HIGH);
        digitalWrite(lights[3], HIGH);
      }
      if (i == 14) {
        digitalWrite(lights[1], HIGH);
        digitalWrite(lights[2], HIGH);
        digitalWrite(lights[3], HIGH);
      }
      if (i == 15) {
        digitalWrite(lights[j], HIGH);
      }

    }
    delay(1000);


  }

}

Using Array of HIGH and LOW

int red = 8;
int blue = 10;
int green = 12;
int yellow = 13;
int lights[] = {red, blue, green, yellow};
int numOfLights = sizeof(lights)/sizeof(int);
int lightDelay = 500;



void setup() {
  // put your setup code here, to run once:
  for (int j = 0; j < numOfLights; j++) {
    pinMode(lights[j], OUTPUT);
  }


}

void loop() {

  //go from 1 to 15
  for (int x = 1; x <= 15; x++) {
    // array to store the HIGH and LOW values
    // 0 means low and 1 means high
    int a[] = {0, 0, 0, 0};
    int n = x;
    // get the array values [a,b,c,d]
    for (int i = 0; n > 0; i++) {
      a[i] = n % 2;
      n = n / 2;
    }
    // now we get high and low values, put them to the lights
    for (int j = 0; j < numOfLights; j++) {
      digitalWrite(lights[j], a[j]);
    }
    delay(500);
  }
  delay(500);

}