c++ function to find length of array

// array::size
#include <iostream>
#include <array>

int main ()
{
  std::array<int,5> myints;
  std::cout << "size of myints: " << myints.size() << std::endl;
  std::cout << "sizeof(myints): " << sizeof(myints) << std::endl;

  return 0;
}// C++ program to find size of an array by using a  
// pointer hack. 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
    int  arr[] = {1, 2, 3, 4, 5, 6}; 
    int size = *(&arr + 1) - arr; 
    cout << "Number of elements in arr[] is "
         << size; 
    return 0; 
} 
// C++ program to find size of an array by writing our 
// sizeof 
#include <bits/stdc++.h> 
using namespace std; 
  
// User defined sizeof macro 
# define my_sizeof(type) ((char *)(&type+1)-(char*)(&type)) 
  
int main() 
{ 
    int  arr[] = {1, 2, 3, 4, 5, 6}; 
    int size = my_sizeof(arr)/my_sizeof(arr[0]); 
  
    cout << "Number of elements in arr[] is " 
         << size; 
  
    return 0; 
}