43. Safe Initialization

#include <iostream>
using namespace std;

int main() {
    cout << NULL << "\n";
	cout << nullptr;
}

Solution Details

• nullptr is type-safe (std::nullptr_t).
   
• NULL is a macro (typically defined as 0).
   
• Both behave the same in boolean checks (if (p)), but nullptr avoids overload ambiguities.
  
   

👉 In simple words:

• p1 = nullptr; → “This is a pointer with no address.”
• p2 = NULL; → “This is just zero, used like a pointer.”
  
   

Significance for Embedded Developers

• When initializing pointers to resources (UART, GPIO, DMA), prefer nullptr to avoid bugs.
   

Example:

 Uart* handle = nullptr; // safe default

if (handle) { /* use safely */ }

• This makes firmware code clearer and safer than using NULL.