How to print size of array parameter in C++?

Example:

#include <iostream>
 using namespace std;
 
 void findSize(int arr[])
 {
  cout << sizeof(arr) << endl;
 }
 
 int main()
 {
  int a[10];
  cout << sizeof(a) << " ";
  findSize(a);
  return 0;
 }

Output:

The above output is for a machine where size of integer is 4 bytes and size of a pointer is 8 bytes.

The cout statement inside main prints 40, and cout in findSize prints 8. The reason is, arrays are always passed pointers in functions, i.e., findSize(int arr[]) and findSize(int *arr) mean exactly same thing. Therefore the cout statement inside findSize() prints size of a pointer.

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