// this code illustrates pointers to basic types
#include <iostream>
#include <cstdint>
using namespace std;

void multiply_by_8(int *value_pointer) {
  cout << "Value pointer's value: " << hex << int64_t(value_pointer) << endl;
  cout << "What value pointer points *at*, before multiplying: " 
       << dec << *value_pointer << endl;
  // do it in two steps, just because
  *value_pointer = *value_pointer * 2;
  // alternative way:
  *value_pointer = *value_pointer << 2; // multiply by 4
}

int main() {
  {
    // call multiply_by_8 to show passing data by pointer
    int value = 7;
    multiply_by_8(&value);
    cout << "7 times 8 = " << dec << value << endl;
  }
  {
    // further code manipulating a value through a pointer

    int some_number = 60;
    int *pointer_to_some_number = &some_number;
    cout << "Enter divisor: ";
    int divisor;
    cin >> divisor;
    *pointer_to_some_number /= divisor;
    cout << "After dividing by " << divisor << ", some number is "
         << some_number << endl;
    cout << "Address of some_number: " << hex << int64_t(&some_number) << endl;
    cout << "  ... and its pointer:  " << hex << int64_t(pointer_to_some_number)
         << endl;

    multiply_by_8(pointer_to_some_number); // note we just pass the pointer!
    cout << "At end, number is " << some_number << endl;
  }
  return 0;
}