C Programming - MCQ Practice Questions

The <stdlib.h> header file contains declarations for malloc(), calloc(), realloc(), and free() functions.

calloc() takes two arguments (number of elements and size) and initializes all allocated bytes to zero, unlike malloc().

free() is the standard function to deallocate memory previously allocated by malloc(), calloc(), or realloc().

sizeof(int) * 10 = 4 * 10 = 40 bytes on a 32-bit system.

All memory allocation and deallocation functions are declared in <stdlib.h>.

calloc() takes two parameters (count, size) and initializes memory to 0, while malloc() takes one parameter and leaves memory uninitialized.

According to C standard, free(NULL) is safe and does nothing.

Dynamic memory allows flexible sizing at runtime, which static arrays cannot provide.

Both A and B allocate memory correctly; B includes explicit typecasting which is optional in C but good practice.

stdlib.h contains malloc(), calloc(), realloc(), and free() functions for dynamic memory management.

malloc() returns a generic pointer (void*) which can be cast to any data type pointer.

calloc(num, size) allocates num * size = 10 * 4 = 40 bytes total.

stdlib.h contains declarations for malloc(), calloc(), realloc(), and free() functions.

free() is used to deallocate memory that was previously allocated using malloc(), calloc(), or realloc().

calloc() allocates memory and initializes all bytes to zero, while malloc() leaves the allocated memory uninitialized.

calloc(5, sizeof(int)) allocates memory for 5 integers and initializes all to zero.

malloc() is the standard C library function for dynamic memory allocation. It takes the number of bytes to allocate as an argument and returns a pointer to the allocated memory.

<stdlib.h> is the standard header file containing declarations for malloc(), calloc(), realloc(), and free() functions.

When malloc() cannot allocate the requested memory, it returns NULL. The programmer must check for NULL before using the pointer to avoid undefined behavior.

Calling free(NULL) is safe in C and does nothing. This is by design, allowing you to write code like free(ptr) without checking if ptr is NULL first.