C Arrays Quiz – 20 Questions with Answers
20 questions · 15 min · Medium
C Preprocessor Quiz – 15 Questions with Answers
Test your knowledge of the C preprocessor with 15 questions covering preprocessor directives, macros, header files, conditional compilation, include files, and predefined macros.
- 15
- Questions
- 12 min
- Time limit
- Medium
- Difficulty
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All 15 questions and answers Spoilers: this shows the questions and answers. Try the quiz first! Open
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1. What is the primary purpose of the C preprocessor?
- A. To execute the C program
- B. To process source code before compilation
- C. To allocate memory at runtime
- D. To debug the program
Show answer
B. To process source code before compilation
The C preprocessor processes directives and performs tasks such as macro expansion and header inclusion before the source code is compiled.
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2. Which symbol begins a preprocessor directive in C?
- A. $
- B. @
- C. #
- D. %
Show answer
C. #
C preprocessor directives begin with the # symbol, such as #include and #define.
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3. Which preprocessor directive is used to define a macro?
- A. #macro
- B. #define
- C. #constant
- D. #def
Show answer
B. #define
The #define directive is used to define object-like and function-like macros.
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4. What does the following directive do? #define PI 3.14159
- A. Creates a runtime variable named PI
- B. Defines a macro named PI
- C. Creates a function named PI
- D. Allocates memory for PI
Show answer
B. Defines a macro named PI
The #define directive creates a macro. During preprocessing, occurrences of PI are replaced according to the macro definition.
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5. Which preprocessor directive is used to include a header file?
- A. #include
- B. #header
- C. #import
- D. #using
Show answer
A. #include
The #include directive tells the preprocessor to include the contents of another file at that point in the source.
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6. Which syntax is commonly used to include a standard C library header?
- A. #include <stdio.h>
- B. #include (stdio.h)
- C. #header <stdio.h>
- D. include [stdio.h]
Show answer
A. #include <stdio.h>
Angle brackets are commonly used with #include for system or standard headers, such as #include <stdio.h>.
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7. Which syntax is commonly used to include a user-defined header file?
- A. #include <myheader.h>
- B. #include "myheader.h"
- C. #header "myheader.h"
- D. #import "myheader.h"
Show answer
B. #include "myheader.h"
Double quotes are commonly used when including user-defined headers, such as #include "myheader.h".
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8. Which directive is used for conditional compilation when a macro is defined?
- A. #ifdef
- B. #ifdefined
- C. #condition
- D. #defined
Show answer
A. #ifdef
#ifdef conditionally includes code when the specified macro has been defined.
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9. Which directive is used to test whether a macro has not been defined?
- A. #ifnot
- B. #ifndef
- C. #notdefined
- D. #undefine
Show answer
B. #ifndef
#ifndef means 'if not defined' and conditionally includes code when the specified macro is not defined.
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10. What does the #undef directive do?
- A. Creates a new macro
- B. Removes the definition of a macro
- C. Includes a header file
- D. Stops compilation permanently
Show answer
B. Removes the definition of a macro
The #undef directive cancels the current definition of a macro.
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11. Which directive provides an alternative block when an #if condition is false?
- A. #otherwise
- B. #else
- C. #alternative
- D. #default
Show answer
B. #else
The #else directive specifies the alternative section of code when the preceding conditional preprocessing condition is false.
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12. Which directive ends a conditional preprocessing block?
- A. #end
- B. #endif
- C. #end if
- D. #stop
Show answer
B. #endif
The #endif directive marks the end of a conditional preprocessing block started by directives such as #if, #ifdef, or #ifndef.
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13. What is the main advantage of function-like macros?
- A. They can represent reusable code-like substitutions
- B. They always provide type safety
- C. They are stored as runtime functions
- D. They automatically allocate memory
Show answer
A. They can represent reusable code-like substitutions
Function-like macros can accept arguments and perform textual substitution during preprocessing, allowing reusable code patterns.
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14. Which predefined macro is commonly used to obtain the current source file name?
- A. __FILE__
- B. __SOURCE__
- C. __NAME__
- D. __FILENAME__
Show answer
A. __FILE__
The predefined macro __FILE__ expands to the name of the current source file as a string literal.
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15. Which predefined macro is commonly used to obtain the current source line number?
- A. __LINE__
- B. __ROW__
- C. __LINE_NUMBER__
- D. __SOURCE_LINE__
Show answer
A. __LINE__
The predefined macro __LINE__ expands to the current source line number and is commonly useful for diagnostics and debugging.