realloc function - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to allocate memory for 10 integers using malloc.

C

#include <stdlib.h>

int *arr = (int *)[1](10 * sizeof(int));

Drag options to blanks, or click blank then click option'

Amalloc

Brealloc

Ccalloc

Dfree

Attempts:

3 left

💡 Hint

Common Mistakes

Using realloc before any memory is allocated.

Using free instead of malloc.

The malloc function allocates memory without initializing it. Here, it allocates space for 10 integers.

2fill in blank

medium

Complete the code to resize the memory block pointed by arr to hold 20 integers using realloc.

C

arr = (int *)[1](arr, 20 * sizeof(int));

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Amalloc

Bcalloc

Crealloc

Dfree

Attempts:

3 left

💡 Hint

Common Mistakes

Using malloc instead of realloc to resize memory.

Not casting the return value of realloc.

The realloc function changes the size of the memory block pointed to by arr. It can increase or decrease the size.

3fill in blank

hard

Fix the error in the code to safely resize memory and check for allocation failure.

C

int *temp = (int *)[1](arr, 30 * sizeof(int));
if (temp == NULL) {
    // handle error
} else {
    arr = temp;
}

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Arealloc

Bmalloc

Ccalloc

Dfree

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning realloc result directly to original pointer without checking for NULL.

Using free instead of realloc.

Use realloc to resize the memory block. Always assign the result to a temporary pointer to avoid losing the original pointer if allocation fails.

4fill in blank

hard

Fill both blanks to create a new array with double the size of the old one using realloc and initialize new elements to zero.

C

int old_size = 10;
int new_size = old_size * 2;
int *temp = (int *)[1](arr, new_size * sizeof(int));
if (temp != NULL) {
    for (int i = old_size; i < new_size; i++) {
        temp[i] = [2];
    }
    arr = temp;
}

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Arealloc

Bmalloc

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using malloc instead of realloc for resizing.

Initializing new elements with 1 instead of 0.

realloc resizes the array. The new elements from old_size to new_size are set to zero to initialize them.

5fill in blank

hard

Fill all three blanks to safely resize an integer array, check for failure, and update the pointer.

C

int *temp = (int *)[1](arr, [2] * sizeof(int));
if (temp == [3]) {
    // handle allocation failure
} else {
    arr = temp;
}

Drag options to blanks, or click blank then click option'

Amalloc

Brealloc

C20

DNULL

Attempts:

3 left

💡 Hint

Common Mistakes

Using malloc instead of realloc for resizing.

Checking against 0 instead of NULL.

Not checking for allocation failure before updating pointer.

Use realloc to resize the array to hold 20 integers. Check if the returned pointer is NULL to detect failure before updating the original pointer.