File Handling, Preprocessor, Compilation, and Makefiles

Question 1

Fill in the blank: To create a binary file for writing, use mode _______.

Answer 1

wb

Question 2

What is the action of the function fputs()?

Answer 2

Write a string.

Question 3

What does fprintf() do?

Answer 3

Writes to a file like printf().

Question 4

What is the purpose of the function fseek()?

Answer 4

Jump to a specific position in a file.

Question 5

What is the role of errno in error handling?

Answer 5

Global variable to check errors.

Question 6

What are the three standard streams in C?

Answer 6

stdin, stdout, stderr

Question 7

What does stdout represent?

Answer 7

Standard output (console).

Question 8

What is the result of the command ./myprogram > output.txt 2> errors.txt?

Answer 8

Saves stdout in output.txt and stderr in errors.txt.

Question 9

What happens when you reach the end of a file (EOF)?

Answer 9

Stops reading.

Question 10

What is the summary takeaway regarding file operations?

Answer 10

Always check if fopen() worked before reading/writing.

Question 11

True or False: The function remove() is used to delete a file.

Answer 11

True.

Question 12

What is the C Preprocessor?

Answer 12

Preprocessor expands macros, includes headers, removes comments, and modifies source code before compilation.

Question 13

What does the directive #include <file> do?</file>

Answer 13

Includes a system header file.

Question 14

What does the directive #include “file” do?

Answer 14

Includes a user-defined header file.

Question 15

What is the purpose of #define MACRO?

Answer 15

Defines a macro (a shortcut for values or code).

Question 16

What happens when #ifdef MACRO is used?

Answer 16

Compiles code only if a macro is defined.

Question 17

What does #ifndef MACRO do?

Answer 17

Compiles code only if a macro is NOT defined.

Question 18

What is the function of #undef MACRO?

Answer 18

Undefines a macro.

Question 19

What does the #pragma directive provide?

Answer 19

Compiler-specific instructions (rarely used).

Question 20

What are system headers and how are they included?

Answer 20

System headers are included using angle brackets < >, e.g., #include <stdio.h>.</stdio.h>

Question 21

What are user-defined headers and how are they included?

Answer 21

User-defined headers are included using quotes “ “, e.g., #include “myfile.h”.

Question 22

What does #define PI 3.14159 accomplish?

Answer 22

Replaces every PI in the code with 3.14159.

Question 23

What is a common pitfall when using macros?

Answer 23

Not using parentheses can lead to unexpected results.

Question 24

How can the MAX macro be defined correctly?

Answer 24

define MAX(a, b) ((a) > (b) ? (a) : (b))

Question 25

What does stringifying macros do?

Answer 25

Converts macro arguments into strings.

Question 26

What is the benefit of structuring code?

Answer 26

Makes code easier to read, allows reusability, and improves debugging and maintainability.

Question 27

What are the components of a structured project?

Answer 27

* myProgram.c (Main Program) * myProgram.h (Header File) * stack.c (Stack Implementation) * stack.h (Stack Function Declarations)

Question 28

What do header files contain?

Answer 28

Function declarations and constants.

Question 29

What do source files contain?

Answer 29

Function definitions.

Question 30

What is the purpose of #ifndef STACK_H?

Answer 30

Prevents multiple inclusions (include guards).

Question 31

What are the three stages of compilation?

Answer 31

* Preprocessing * Compilation * Linking

Question 32

What command compiles source files separately?

Answer 32

gcc -c stack.c -o stack.o

Question 33

What is the command to link object files?

Answer 33

gcc stack.o myProgram.o -o myProgram

Question 34

What is the purpose of a Makefile?

Answer 34

Saves time when recompiling large projects, tracks dependencies, and reduces manual errors.

Question 35

What command is used to build a project using a Makefile?

Answer 35

make

Question 36

What is a library in C?

Answer 36

A collection of precompiled functions that can be used in multiple projects.

Question 37

What is the difference between a static library and a shared library?

Answer 37

* Static Library (.a): Linked at compile time (larger executable) * Shared Library (.so): Linked at runtime (smaller executable)

Question 38

What command links the math library?

Answer 38

gcc myMaths.c -lm -o myMaths

Question 39

What does the -lm flag do?

Answer 39

Tells GCC to link the math library.

Question 40

What does the preprocessor do?

Answer 40

Expands macros, includes headers, and modifies code.