NULL vs. nullptr: Why the C Change?

NULL vs nullptr: Why the Replacement?

The replacement of NULL with nullptr in C was motivated by several reasons, including:

1. Type Safety:

nullptr is a strongly-typed constant of type std::nullptr_t, while NULL is an integer constant that can be converted to any pointer type. This difference ensures type safety and prevents accidental conversion of NULL to a different pointer type.

2. Overload Resolution Ambiguity:

NULL can lead to ambiguity in function overload resolution. For instance, consider the following two functions:

void f(int);
void f(foo*);

With NULL, it would be unclear which function to call when passing NULL as an argument. nullptr, on the other hand, will only match the second function, as it is implicitly convertible to any pointer type.

3. Portability:

NULL is a macro defined in C, while nullptr is part of the C standard library. This difference makes nullptr more portable and ensures consistent behavior across different compilers.

Benefits of Using nullptr:

• Improved type safety: Prevents accidental conversion to non-pointer types.
• Reduced ambiguity in overload resolution: Ensures correct function matching.
• Enhanced portability: Avoids platform-dependent definitions of NULL.

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