Day#61 'C' Coding Challenge

Question 1: Which data type is NULL in c Programming Language?

Question 2: What is the output of the below program?

#include<stdio.h> #define NULL 0 void main() { printf("%d",sizeof(NULL)); }

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NULL is not a variable in C. It is a predefined constant without any data type associated. It has a value of Zero.

The definition of  NULL is as follows:

#define NULL ((void *)0)

A NULL can be defined in the program and can be compiled without any error. However, considering that it is pre-defined, it is preferable not to re-define NULL.

The statement printf("%d",sizeof(NULL)); prints the sizeof NULL (which holds the integer value) and hence size of integer shall be printed which is 4 bytes (either in 32-bit or 64-bit system)