How to resolve the algorithm Pragmatic directives step by step in the C programming language

Published on 7 June 2024 03:52 AM
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How to resolve the algorithm Pragmatic directives step by step in the C programming language

Table of Contents

Problem Statement

Pragmatic directives cause the language to operate in a specific manner,   allowing support for operational variances within the program code   (possibly by the loading of specific or alternative modules).

List any pragmatic directives supported by the language,   and demonstrate how to activate and deactivate the pragmatic directives and to describe or demonstrate the scope of effect that the pragmatic directives have within a program.

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Pragmatic directives step by step in the C programming language

The code begins by including the standard input/output library <stdio.h>.

Then, it defines a macro Hi using the #define directive. This macro, when invoked, will print the string "Hi There." to the standard output.

Next, the start and end macros are defined to represent the beginning and end of the main function, respectively.

The start macro is invoked, followed by the Hi macro. This prints "Hi There." to the standard output.

The code then uses the #warning directive to generate a warning message. The #warning directive is only supported by C99 and later compilers like GCC. The warning message is "Don't you have anything better to do ?"

The code then uses the #ifdef directive to check if the program is being compiled on a Unix system. If so, it prints "This is an Unix system." to the standard output. If the program is being compiled on a Windows system, it prints "This is a 32 bit Windows system." or "This is a 64 bit Windows system.", depending on whether the system is 32-bit or 64-bit.

Finally, the end macro is invoked to end the main function.

The code is a bit tongue-in-cheek and demonstrates some of the more unusual features of the C preprocessor.

Source code in the c programming language

/*Almost every C program has the below line, 
the #include preprocessor directive is used to 
instruct the compiler which files to load before compiling the program.

All preprocessor commands begin with #
*/
#include<stdio.h> 

/*The #define preprocessor directive is often used to create abbreviations for code segments*/
#define Hi printf("Hi There.");

/*It can be used, or misused, for rather innovative uses*/

#define start int main(){
#define end return 0;}

start

Hi

/*And here's the nice part, want your compiler to talk to you ? 
Just use the #warning pragma if you are using a C99 compliant compiler
like GCC*/
#warning "Don't you have anything better to do ?"

#ifdef __unix__
#warning "What are you doing still working on Unix ?"
printf("\nThis is an Unix system.");
#elif _WIN32
#warning "You couldn't afford a 64 bit ?"
printf("\nThis is a 32 bit Windows system.");
#elif _WIN64
#warning "You couldn't afford an Apple ?"
printf("\nThis is a 64 bit Windows system.");
#endif

end

/*Enlightened ?*/


  

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