Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.Learn Symbolic Constant | Macros
C Preprocessing

Swipe to show menu

book
Symbolic Constant

Each #define line consists of three parts:

The body of a macro can be not only a single numeric value, but also other macros or entire expressions:

main.c

main.c

copy

              
12345678910

            
#include <stdio.h>
#define TWO 2                                // macros with value.
#define RESULT TWO*TWO                       // TWO is replaced by the number 2.
#define PRINT printf("result = %d", RESULT);

int main() 
{
   PRINT 
   return 0;
}

Every time the compiler encounters β€œTWO”, it will simply substitute its value 2.

The macro is immutable. Once defined, it is a permanent textual substitution within the file or scope where it is defined.

Why do we need this? Why not just use variables?

What is better to use?:

  • If the value never changes, const is better, because it is safer;

  • If you need to substitute a simple number or text, you can use a macro.

  1. Create an object macro add, the body of the macro is an addition operator +.

  2. Use a macro to add any two numbers.

Task

Swipe to start coding

  1. Create an object macro add, the body of the macro is an addition operator +;
  2. Use a macro to add any two numbers.

Solution

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 2. ChapterΒ 1
single

single

Ask AI

expand

Ask AI

ChatGPT

Ask anything or try one of the suggested questions to begin our chat

close

Awesome!

Completion rate improved to 5.56

book
Symbolic Constant

Each #define line consists of three parts:

The body of a macro can be not only a single numeric value, but also other macros or entire expressions:

main.c

main.c

copy

              
12345678910

            
#include <stdio.h>
#define TWO 2                                // macros with value.
#define RESULT TWO*TWO                       // TWO is replaced by the number 2.
#define PRINT printf("result = %d", RESULT);

int main() 
{
   PRINT 
   return 0;
}

Every time the compiler encounters β€œTWO”, it will simply substitute its value 2.

The macro is immutable. Once defined, it is a permanent textual substitution within the file or scope where it is defined.

Why do we need this? Why not just use variables?

What is better to use?:

  • If the value never changes, const is better, because it is safer;

  • If you need to substitute a simple number or text, you can use a macro.

  1. Create an object macro add, the body of the macro is an addition operator +.

  2. Use a macro to add any two numbers.

Task

Swipe to start coding

  1. Create an object macro add, the body of the macro is an addition operator +;
  2. Use a macro to add any two numbers.

Solution

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

close

Awesome!

Completion rate improved to 5.56

Swipe to show menu

some-alt