Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to check if a variable is NULL in C/C++?
In C or C++, there is no special method for comparing NULL values. We can use if statements to check whether a variable is null or not.
Here we will see one program. We will try to open a file in read mode, that is not present in the system. So the function will return null value. We can check it using if statement. See the code for better understanding.
Example Code
#include <stdio.h>
main() {
//try to open a file in read mode, which is not present
FILE *fp;
fp = fopen("hello.txt", "r");
if(fp == NULL)
printf("File does not exists");
fclose(fp);
}Output
File does not exists
Updated on: 30-Jul-2019
20K+ Views
Advertisements