Pointers, Dynamic Memory, Linked Lists, and File I/O

Question 1

What is pointer arithmetic?

Answer 1

Performing arithmetic operations on pointers.

Question 2

Fill in the blank: A void pointer (void *) is a _______.

Answer 2

Generic pointer that can store addresses of any data type.

Question 3

What function is used for dynamic memory allocation?

Answer 3

malloc()

Question 4

What should you always check after using malloc()?

Answer 4

If malloc() succeeds.

Question 5

What function is used to release allocated memory?

Answer 5

free()

Question 6

What are common pitfalls related to pointers?

Answer 6

• Memory Leaks
• Dangling Pointers
• Wild Pointers

Question 7

What is a segmentation fault?

Answer 7

Occurs when trying to access memory illegally.

Question 8

What tool can be used for memory debugging?

Answer 8

valgrind

Question 9

True or False: Pointer arithmetic follows the size of the data type.

Answer 9

True.

Question 10

What happens if you forget to free memory?

Answer 10

Memory leaks occur.

Question 11

What is a dangling pointer?

Answer 11

Using a pointer after the memory it points to has been freed.

Question 12

What is a wild pointer?

Answer 12

Using uninitialized pointers.

Question 13

What does p++ do if p is a pointer to an int?

Answer 13

Moves p to the next int (increases by sizeof(int)).

Question 14

What happens when you write beyond allocated space?

Answer 14

It can corrupt adjacent memory.

Question 15

What is the output of printf(“p = %p, *p = %c\n”, p, *p) if p points to ‘A’?

Answer 15

p= 0x1e224eff, *p= A

Question 16

Fill in the blank: The function _______ is used to allocate memory for an array of integers.

Answer 16

malloc()

Question 17

What is Pass by Value?

Answer 17

A copy of the variable is passed to the function, keeping the original variable unchanged.

Question 18

What is a downside of Pass by Value?

Answer 18

Can be inefficient for large data structures.

Question 19

How does Pass by Reference work?

Answer 19

A pointer to the variable is passed instead of a copy, allowing the original variable to be modified.

Question 20

What is a pointer in C?

Answer 20

A pointer stores the memory address of another variable.

Question 21

What is the syntax to dereference a pointer?

Answer 21

Using the asterisk (*) before the pointer variable.

Question 22

What is a function pointer?

Answer 22

A function pointer stores the address of a function.

Question 23

Why use function pointers?

Answer 23

Makes code modular and reusable; enables dynamic function execution.

Question 24

What is a key advantage of linked lists over arrays?

Answer 24

They do not need a predefined size and allow efficient insertions and deletions.

Question 25

What is the basic structure of a linked list node?

Answer 25

struct Node { int data; struct Node *next; };

Question 26

How do you insert a node at the beginning of a linked list?

Answer 26

Create a new node, set its next to the current head, and update the head to the new node.

Question 27

What is the purpose of the printList function?

Answer 27

To traverse and print all the nodes in the linked list.

Question 28

True or False: Pass by reference allows modifying original values.

Answer 28

True.

Question 29

Fill in the blank: _______ enables dynamic execution of functions.

Answer 29

Function pointers.

Question 30

Final takeaway: What do linked lists provide compared to arrays?

Answer 30

More flexibility for dynamic data storage.

Question 31

What is the purpose of scanf() in C?

Answer 31

Takes user input.

Question 32

What does scanf() return?

Answer 32

Number of values successfully assigned.

Question 33

What happens if input fails in scanf()?

Answer 33

Exits the loop.

Question 34

Define a stream in the context of programming.

Answer 34

A way of handling data flow in a program.

Question 35

What are the key features of a stream?

Answer 35

* Abstracts file handling * Buffered * Two types: Text Streams and Binary Streams

Question 36

What is the function to open a file in C?

Answer 36

fopen()

Question 37

What is the function to close a file in C?

Answer 37

fclose()

Question 38

What does a file pointer (FILE *) do?

Answer 38

Accesses files in C.

Question 39

What does fopen() return if it fails?

Answer 39

NULL

Question 40

What mode is used to open a text file for reading?

Answer 40

"r"