In which header file NULL macro is defined ?

Question

Question

This question was previously asked in

NIELIT Scientific Assistant IT 5 Dec 2021 Official Paper

Answer 1

The correct answer is option 1: stdio.h and stddef.h

Key Points

NULL is a macro representing a null pointer constant.
It is defined as #define NULL ((void*)0) in C.
In C language, the NULL macro is defined in both:
- <stdio.h>: Standard Input Output header
- <stddef.h>: Standard Definitions header

Additional Information

iostream.h: Used in C++ for input-output operations, but not related to defining NULL.
string.h: Used for string manipulation functions, does not define NULL.
Pre-processor: Though macros are handled by the pre-processor, NULL is defined in header files, not directly by the pre-processor.

Hence, the correct answer is: option 1: stdio.h and stddef.h