how to check the length of an array in c++ code example

Example 1: c++ get length of array

int arr[5];
int len = sizeof(arr) / sizeof(arr[0]);
// returns 5

Example 2: array length c++

#include <iostream>
using namespace std;

#define size(type) ((char *)(&type+1)-(char*)(&type))

int main(){
  int arr[5] = {1, 2, 3, 4, 5};
  cout << size(arr) / size(arr[0]) << endl; //returns 5
  //alternatively
  cout << sizeof(arr) / sizeof(int) << endl; //returns 5
}