Arduino No Libary Stepper Motor

//For motor: Nema 17 Bipolar Stepper 17HS13-0404S1
int motorPin1 = 8; //BLÅ (Blue)
int motorPin2 = 9; //SORT (Black)
int motorPin3 = 10; //GRØN (Green)
int motorPin4 = 11; //RØD (Red)
int delayTime = 5;

void setup() {
  Serial.begin(9600);
  pinMode(motorPin1, OUTPUT);
  pinMode(motorPin2, OUTPUT);
  pinMode(motorPin3, OUTPUT);
  pinMode(motorPin4, OUTPUT);
}

int stepmode = 0;

void steponce(){
  switch(stepmode){
    case 0:
      digitalWrite(motorPin4, HIGH);
      digitalWrite(motorPin3, LOW);
      digitalWrite(motorPin2, LOW);
      digitalWrite(motorPin1, LOW);
      stepmode++;
      break;
    case 1:
      digitalWrite(motorPin4, LOW);
      digitalWrite(motorPin3, HIGH);
      digitalWrite(motorPin2, LOW);
      digitalWrite(motorPin1, LOW);
      stepmode++;
      break;
    case 2:
      digitalWrite(motorPin4, LOW);
      digitalWrite(motorPin3, LOW);
      digitalWrite(motorPin2, HIGH);
      digitalWrite(motorPin1, LOW);
      stepmode++;
      break;
    default:
      digitalWrite(motorPin4, LOW);
      digitalWrite(motorPin3, LOW);
      digitalWrite(motorPin2, LOW);
      digitalWrite(motorPin1, HIGH);
      stepmode = 0;
      break;
  }
  delay(delayTime);
  //Serial.println("Stepped once");
}

void steptimes(int n){
  for(int i = 0; i < n; i++){
    steponce();
  }
  Serial.print("Stepped ");
  Serial.print(n);
  Serial.println(" times");
}

void loop() {
  steptimes(100);
  delay(1000);
}