C Preprocessor MCQs

Question 1

What is the purpose of the #include directive in C preprocessing?

Accepted Answer

To include a header file

Answer

To define a macro

Answer

To declare a variable

Answer

To conditionally compile code

Question 2

What is the purpose of the #if directive in C preprocessing?

Accepted Answer

To conditionally include code

Answer

To check if a variable is declared

Answer

To include a header file

Answer

To define a macro

Question 3

In C, how do you use the #ifdef directive to conditionally include code if a macro is defined?

Accepted Answer

#ifdef MACRO

Answer

#ifdef(MACRO)

Answer

#ifdef:MACRO

Answer

#ifdef: MACRO

Question 4

What is the purpose of the #error directive in C preprocessing?

Accepted Answer

To include an error message in the code

Answer

To define a macro

Answer

To check if a variable is declared

Answer

To conditionally compile code

Question 5

What is the result of the #ifndef DEBUG directive if the DEBUG macro is defined?

Accepted Answer

The code block following it is excluded

Answer

The code block following it is included

Answer

It generates a compilation error

Answer

It defines the DEBUG macro

Question 6

Which directive in C preprocessing is used to concatenate two or more strings?

Accepted Answer

#define

Answer

#concat

Answer

#strcat

Answer

#combine

Question 7

In C, what does the #line directive do in C preprocessing?

Accepted Answer

Specifies the line number in the source file

Answer

Defines a macro

Answer

Includes a header file

Answer

Excludes code

Question 8

What is the purpose of the #pragma once directive in C preprocessing?

Accepted Answer

Prevents recursive inclusion of header files

Answer

Defines a macro

Answer

Checks for syntax errors

Answer

Excludes code

Question 9

In C preprocessing, what is the purpose of the #elif directive?

Accepted Answer

Provides an alternative condition

Answer

Checks if a macro is defined

Answer

Checks if a macro is not defined

Answer

Defines a macro