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C Preprocessing
course content

Course Content

C Preprocessing

C Preprocessing

1. Introduction to Preprocessing
Introduction to Compilation StagesRole of the PreprocessorPreprocessing Commands
2. Macros
Symbolic ConstantMacro With ArgumentsAdvanced Usage of Symbolic ConstantCancel MacroStringify Operators
3. Conditional compilation
Fundamentals of Conditional CompilationPitfalls and Best Practices

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.
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

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Section 2. Chapter 1
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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.
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!

Section 2. Chapter 1
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
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