int i = 1;

void setup() {
  for (i; i < 11; i = i + 1) {
    pinMode(i, OUTPUT);
  }
}
void loop() {
  for (i; i < 11; i = i + 1) {
    digitalWrite(i, HIGH);
    delay(50);
  }
  alleAus();
}

void alleAus() {
  for (i = 1; i < 11; i = i + 1) {
    digitalWrite(i, LOW);
  }