passing arrays by reference

Arrays (which actually are pointers) pass by reference by default.

void function(int arr[]);

void setup(){
  Serial.begin(9600);
  
}

void loop(){
  int counter[10];
  funtion(cunter);
  for(int i=0;i<10;i++){
    Serial.println(counter[i]);
  }
}

void function(int arr[]){
  for(int i=0;i<10;i++){
    arr[i]=(i*10);
  }
}