UrbanPro
Login Ask & Answer Success Stories Paid Courses Free Classes Tuition & Classes Fees Write a Review All Categories Help Center
Post your Learning Need Signup as a Tutor
✕

Popular Cities

Bangalore

Hyderabad

Delhi

Mumbai

Chennai

Pune

Kolkata

Gurgaon

Ahmedabad

Jaipur

Noida

✕

Learn C Language from the Best Tutors

  • Affordable fees
  • 1-1 or Group class
  • Flexible Timings
  • Verified Tutors

Book a Free Demo

C Language > Learn C Language > How do you override a defined macro?
✕

Search in

How do you override a defined macro?

Asked by Last Modified  

12 Answers

Learn C Language

Follow 1
Answer

Please enter your answer

Professional Tutor with 15 years of experience.

We can use the #ifdef and #undef directive to undefine a previously defined macro.
Comments
Dislike Bookmark

#define MYMACRO(x) x*x //previously defined macro ... #ifdef MYMACRO #undef MYMACRO #define MYMACRO(x) x*x*x //new definition #endif int main() { printf("%d\n", MYMACRO(2)); return 0; }
Comments
Dislike Bookmark

You can't. The command line is handled before any source and header files. If a source file defines a macro, then it must not be defined before, and will get the new value from now on. The only way to change it, is to #undef and #define it again, at a later point. If you have access to a header...
read more
You can't. The command line is handled before any source and header files. If a source file defines a macro, then it must not be defined before, and will get the new value from now on. The only way to change it, is to #undef and #define it again, at a later point. If you have access to a header that is included after the definition, then you have a chance. read less
Comments
Dislike Bookmark

Science Expert, C & C++ Strong

You can use the #undef preprocessor directive to undefine (override) a previously defined macro. Many programmers like to ensure that their applications are using their own terms when defining symbols such as TRUE and FALSE. Your program can check to see whether these symbols have been defined already,...
read more
You can use the #undef preprocessor directive to undefine (override) a previously defined macro. Many programmers like to ensure that their applications are using their own terms when defining symbols such as TRUE and FALSE. Your program can check to see whether these symbols have been defined already, and if they have, you can override them with your own definitions of TRUE and FALSE. read less
Comments
Dislike Bookmark

How do you override a defined macro? in C programming How do you override a defined macro? You can use the #undef preprocessor directive to undefine (override) a previously defined macro. Many programmers like to ensure that their applications are using their own terms when defining symbols such as...
read more
How do you override a defined macro? in C programming How do you override a defined macro? You can use the #undef preprocessor directive to undefine (override) a previously defined macro. Many programmers like to ensure that their applications are using their own terms when defining symbols such as TRUE and FALSE. Your program can check to see whether these symbols have been defined already, and if they have, you can override them with your own definitions of TRUE and FALSE. The following portion of code shows how this task can be accomplished: ... #ifdef TRUE /* Check to see if TRUE has been defined yet */ #undef TRUE /* If so, undefine it */ #endif #define TRUE 1 /* Define TRUE the way we want it defined */ #ifdef FALSE /* Check to see if FALSE has been defined yet */ #undef FALSE /* If so, undefine it */ #endif #define FALSE !TRUE /* Define FALSE the way we want it defined */ ... In the preceding example, the symbols TRUE and FALSE are checked to see whether they have been defined yet. If so, they are undefined, or overridden, using the #undef preprocessor directive, and they are redefined in the desired manner. If you were to eliminate the #undef statements in the preceding example, the compiler would warn you that you have multiple definitions of the same symbol. By using this technique, you can avoid this warning and ensure that your programs are using valid symbol definitions. read less
Comments
Dislike Bookmark

website and mobile application development training, digital marketing training

Yes, You can use the #undef preprocessor directive to undefine (override) a previously defined macro
Comments
Dislike Bookmark

Computer & Maths Professor

You can use the #undef preprocessor directive to undefine (override) a previously defined macro.
Comments
Dislike Bookmark

C and linux Expert

You can use the #undef preprocessor directive to undefine (override) a previously defined macro. Many programmers like to ensure that their applications are using their own terms when defining symbols such as TRUE and FALSE.
Comments
Dislike Bookmark

LearnHowToLearn, Expert In Programming Languages

Just redefine it.
Comments
Dislike Bookmark

LearnHowToLearn, Expert In Programming Languages

#undef first the already defined macro and then redefine it. # define
Comments
Dislike Bookmark

View 10 more Answers

Related Questions

If one leaves a lot of space in a C language code, will it require more space in a hard disk and RAM?
Head files tells system, how to deal with different functions with program such as printf(), scanf() , getche() etc. so you must have reference to it.
Abhishek
0 0
5
What is the best website to learn c language?
NIIT online
Nom
when will you start for delivering lectures on C language
You can approach, I will teach in depth, make you profession c developer
Surbhi

What is void main () into main and what it does?
Void main () is the entry point for execution in C program. The void is a keyword that represents function will not return anything but a void value. Main is the name of the function and () represents...
Noreen
What does # mean in C?
#include is a preprocessor directive which is used to include user-defined file.
Sridevi
0 0
5

Now ask question in any of the 1000+ Categories, and get Answers from Tutors and Trainers on UrbanPro.com

Ask a Question

Related Lessons

PRACTISE makes you PERFECT ; ; ; There is no SUBSTITUTE for HARD WORK ;;;;Breathe SUCCESS like OXYGEN
Proper Planning ( reg what portions to be covered today) revising today's class portions & clarifying doubts solving Maths problems regularly ,noting down formulae separately trying to understand...

Kiruthika S.

1 0
0
How do i get best Campus / Off Campus Placement?
Companies are looking for Skilled Freshers. So build your technical skills while doing MCA / BTech / BCA / BSc (IT or CS) into below areas- 1. Strong your programming & debugging skills ...

Amit K.

0 0
0
C Program Sample Application
//Standard Library Functions(Header Files used) #include<stdio.h> #include <conio.h> //Main method int main() { // function for clearing screen clrscr(); // function to print the output...
S

Salim Ahmed Ansari

0 0
0
Why C is a Language and not a database?
When I interviewed a candidate, I raised this question many times, but I have not got the answer correctly. To under why C is a language and not a database, it is good to understand why our communication...

Vihanga EmbedSoft

0 0
0
Working with C/C++ applications
Inorder to learn C and C++ programming languages one can work with various editors available.To name a few are the most popular one is turbo c++, DEV C++, Eclipse, NetBeans. Here are the screen shots...
S

Salim Ahmed Ansari

0 0
0

Recommended Articles

Lasya Infotech: An educational Training...

Lasya Infotech is a Hyderabad based IT training institute founded in 2016 by O Venkat. Believing in his innovation, passion and persistence and with a diverse blend of experience, he started his brainchild to deliver exemplary professional courses to aspiring candidates by honing their skills. Ever since the institute envisions...

Read full article >

Brilliant Academy, a reputed B. Tech Tuition...

Brilliant Academy is one of the reputed institutes for B.Tech tuition classes. This institute is specialised in delivering quality tuition classes for B.E, Engineering - all streams and Engineering diploma courses. Incorporated in 2012, Brillant Academy is a brainchild of Mr Jagadeesh. The main motto of the academy is to...

Read full article >

Make a Career as a BPO Professional

Business Process outsourcing (BPO) services can be considered as a kind of outsourcing which involves subletting of specific functions associated with any business to a third party service provider. BPO is usually administered as a cost-saving procedure for functions which an organization needs but does not rely upon to...

Read full article >

8 Hottest IT Careers of 2014!

Whether it was the Internet Era of 90s or the Big Data Era of today, Information Technology (IT) has given birth to several lucrative career options for many. Though there will not be a “significant" increase in demand for IT professionals in 2014 as compared to 2013, a “steady” demand for IT professionals is rest assured...

Read full article >

Find C Language Classes near you
C Language Classes in Bangalore
C Language Classes in Hyderabad
C Language Classes in Delhi
C Language Classes in Pune
C Language Classes in Chennai
C Language Classes in Mumbai
C Language Classes in Kolkata
C Language Classes in Ahmedabad
C Language Classes in Noida
C Language Classes in Jaipur

Looking for C Language Classes?

Learn from the Best Tutors on UrbanPro

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you
X

Looking for C Language Classes?

The best tutors for C Language Classes are on UrbanPro

  • Select the best Tutor
  • Book & Attend a Free Demo
  • Pay and start Learning

Learn C Language with the Best Tutors

The best Tutors for C Language Classes are on UrbanPro

This website uses cookies

We use cookies to improve user experience. Choose what cookies you allow us to use. You can read more about our Cookie Policy in our Privacy Policy

Accept All
Decline All

UrbanPro.com is India's largest network of most trusted tutors and institutes. Over 55 lakh students rely on UrbanPro.com, to fulfill their learning requirements across 1,000+ categories. Using UrbanPro.com, parents, and students can compare multiple Tutors and Institutes and choose the one that best suits their requirements. More than 7.5 lakh verified Tutors and Institutes are helping millions of students every day and growing their tutoring business on UrbanPro.com. Whether you are looking for a tutor to learn mathematics, a German language trainer to brush up your German language skills or an institute to upgrade your IT skills, we have got the best selection of Tutors and Training Institutes for you. Read more

ThinkVidya Learning Pvt Ltd © 2010-2025 All Rights Reserved