int[] array = {10,20,30,40,50}
int nr = 5;

int summe = 0;
int i     = nr;

do {
  i = i - 1;
  int no = array[i];
  summe = summe + no;
} while(i!=0);

int mittel = summe / nr;
print(mittel);

void print(int num) {
  int rest = num % 10;
  num = num / 10;
  print(num);
  rest = rest + '0';
  buffer[0] = rest;
  output(buffer);
}