void average(int* num_of_items, double* average)    {
double muuttuja = 0.0;
average = 0.0;

for(int i = 1; i <= num_of_items; i++)  {
scanf("%lf", &muuttuja);
average += muuttuja;
}
double keskiarvo = average/num_of_items;
*average = &keskiarvo;
}