#include <stdio.h>
 
void func(int** arr, int size){
  for(int i=0; i<size; i++){
     *(*arr + i) = (*(*arr+i) + i) % size;
  }
}
 
int main(){
  int arr[] = {3, 1, 4, 1, 5};
  int* p = arr;
  int** pp = &p;
  int num = 6;
  
  func(pp, 5);  
  num = arr[2];
  printf("%d", num);  
 
  return 0;
}