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bookSymbolic 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 “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.
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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.

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bookSymbolic Constant

Stryg for at vise menuen

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 “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.
Opgave

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.

Løsning

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Var alt klart?

Hvordan kan vi forbedre det?

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Sektion 2. Kapitel 1
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