What is conditional preprocessor?

What is conditional preprocessor?

A conditional is a directive that instructs the preprocessor to select whether or not to include a chunk of code in the final token stream passed to the compiler.

What are the two preprocessor statements?

Conditional Compilation Conditional Compilation directives are a type of directive that helps to compile a specific portion of the program or to skip the compilation of some specific part of the program based on some conditions. This can be done with the help of the two preprocessing commands ‘ifdef’ and ‘endif’.

What are conditional inclusions in preprocessor directive?

The preprocessor supports conditional compilation of parts of source file. This behavior is controlled by #if , #else , #elif , #ifdef , #ifndef , #elifdef , #elifndef (since C23), and #endif directives.

What does #ifndef mean in C?

In the C Programming Language, the #ifndef directive allows for conditional compilation. The preprocessor determines if the provided macro does not exist before including the subsequent code in the compilation process.

What is preprocessor with example?

A common example from computer programming is the processing performed on source code before the next step of compilation. In some computer languages (e.g., C and PL/I) there is a phase of translation known as preprocessing. It can also include macro processing, file inclusion and language extensions.

What are preprocessor statements?

Preprocessor statements are handled by the compiler (or preprocessor) before the program is actually compiled. All # statements are processed first, and the symbols (like TRUE) which occur in the C program are replaced by their value (like 1).

What is conditional inclusion in C?

Purpose of a conditional inclusion statement is to allow the program to behave differently from run to run, depending upon the data it is operating on. Conditional inclusion statements are evaluated at compile time or even before compilation by a special program called Preprocessor.

What does Ifdef mean in C?

The #ifdef is one of the widely used directives in C. It allows conditional compilations. During the compilation process, the preprocessor is supposed to determine if any provided macros exist before we include any subsequent code.

What is preprocessor statement?

What are preprocessor commands in C?

C – Preprocessors

Sr.No. Directive & Description
1 #define Substitutes a preprocessor macro.
2 #include Inserts a particular header from another file.
3 #undef Undefines a preprocessor macro.
4 #ifdef Returns true if this macro is defined.

What does #if mean in C?

Description. In the C Programming Language, the #if directive allows for conditional compilation. The preprocessor evaluates an expression provided with the #if directive to determine if the subsequent code should be included in the compilation process.

What is if and endif in PHP?

Definition and Usage The endif keyword is used to mark the end of an if conditional which was started with the if(…): syntax. It also applies to any variation of the if conditional, such as if… elseif and if…else .

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