Dynamic Memory Allocation in C MCQs top 25!

A memory leak in dynamic memory allocation occurs when memory is allocated dynamically during program execution but is not deallocated when it is no longer needed.

When allocating memory for a 2D array using malloc(), you need to ensure that you allocate memory for the entire array, which involves the size of each element (given by sizeof(array_type)) multiplied by the number of rows and columns.

The function used to allocate and initialize memory with zeros in C is `calloc()`.

To allocate memory aligned to a specific byte boundary using aligned_alloc() in C, you use the aligned_alloc() function with two arguments: the size of the memory block (size) and the alignment boundary (alignment).

the sizeof operator is used to determine the size in bytes of a particular data type or variable. It doesn't allocate memory itself but rather provides information about the size of a data type or variable in memory.

To release memory allocated by malloc() in C, you should use the free() function. The correct syntax is free(ptr),

Dynamic memory allocation in C allows you to allocate memory for variables at runtime using functions like malloc(), calloc(), and realloc().

The malloc() function returns a pointer to the beginning of the allocated memory block. The return type is void *, which is a generic pointer type that can be cast to any other pointer type in C.

a function named is_allocated() which could potentially be used to check if a pointer is pointing to allocated memory

The key difference between malloc() and calloc() is that calloc() initializes the allocated memory with zeros, whereas malloc() does not.

Fragmentation in dynamic memory allocation refers to the situation where the memory becomes divided into small, non-contiguous blocks over time due to the allocation and deallocation of memory.

To resize dynamically allocated memory using realloc() in C, you use the realloc() function with the pointer to the previously allocated memory block (ptr) and the new size (new_size) you want to allocate.

The purpose of the `realloc()` function in C is to resize a previously allocated block of memory.

To release memory allocated for a 2D array, you use the free() function with the pointer to the array that was allocated dynamically. This deallocates the memory previously allocated using malloc()

int *ptr = (int *)malloc(sizeof(int));

Dynamic memory allocation offers flexibility but comes with some downsides:

• Slower memory access: Memory allocation and deallocation involve some overhead compared to static allocation, which happens at compile time. However, the performance difference is often negligible in most cases.
• Increased complexity: You're responsible for managing the memory yourself. This includes keeping track of allocated blocks and calling free to avoid memory leaks.

The header file used for dynamic memory allocation functions in C is <stdlib.h>. This header file provides the function prototypes for memory allocation functions like malloc(), calloc(), realloc(), and free()

The memset() function is used to set the memory contents to a specific value by filling a block of memory with a particular byte value.

dynamic memory allocation offers significant flexibility in memory usage at runtime, making it a powerful tool for various programming scenarios, especially when dealing with unknown data sizes or dynamic data structures.

• Dereferencing a null pointer: If malloc or calloc fails to allocate memory, it returns NULL. Trying to access the memory pointed to by a null pointer will lead to a program crash.

To avoid memory fragmentation, allocate and deallocate memory blocks in a balanced manner.

In C, the function used to allocate memory on the heap is malloc(). It is used to dynamically allocate memory of a specified size on the heap during program execution.

If malloc() cannot allocate the requested memory, it returns a NULL pointer.

The alloca() function is used to allocate a block of memory on the program's stack. The stack is a region of memory that grows and shrinks as functions are called and return.