Pointers

Question 1

What is a pointer in C? How do you declare an integer pointer ptr?

Answer 1

A variable that stores the memory address of another variable. Declared as int *ptr;.

Question 2

What are the & and * operators used for with pointers?

Answer 2

& (Address-of Operator): Returns the memory address of a variable.

• (Dereference Operator): Accesses the value at the memory address stored in a pointer.

Question 3

How can you access array elements using pointer arithmetic?

Answer 3

array[i] is equivalent to *(array + i)

Question 4

What is dynamic memory allocation, and what are the four main functions for it in <stdlib.h>?</stdlib.h>

Answer 4

Allocating memory during program execution (runtime). Functions: malloc(), calloc(), realloc(), free().

Question 5

What is the key difference between malloc() and calloc()?

Answer 5

malloc(): Allocates a block of memory, but the allocated memory contains garbage values.

calloc(): Allocates memory for multiple elements and initializes all allocated bytes to zero.

Question 6

Why is it crucial to use free() after dynamic memory allocation?

Answer 6

To deallocate the memory and prevent memory leaks, making it available for reuse.

Question 7

List two drawbacks of using pointers.

Answer 7

Complexity (hard to use/debug), uninitialized pointers (segmentation faults), memory leaks (if not free()d), memory corruption.