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

Cursusinhoud

C Preprocessing

C Preprocessing

1. Introduction to Preprocessing
2. Macros
3. Conditional compilation

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:

c

main

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 “TWO”, 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.
Taak

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.

Oplossing

Switch to desktopSchakel over naar desktop voor praktijkervaringGa verder vanaf waar je bent met een van de onderstaande opties
Was alles duidelijk?

Hoe kunnen we het verbeteren?

Bedankt voor je feedback!

Sectie 2. Hoofdstuk 1
toggle bottom row

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:

c

main

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 “TWO”, 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.
Taak

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.

Oplossing

Switch to desktopSchakel over naar desktop voor praktijkervaringGa verder vanaf waar je bent met een van de onderstaande opties
Was alles duidelijk?

Hoe kunnen we het verbeteren?

Bedankt voor je feedback!

Sectie 2. Hoofdstuk 1
Switch to desktopSchakel over naar desktop voor praktijkervaringGa verder vanaf waar je bent met een van de onderstaande opties
Onze excuses dat er iets mis is gegaan. Wat is er gebeurd?
some-alt