Dynamic memory allocation (heap) in Compiler Design - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to allocate memory dynamically on the heap.

Compiler Design

ptr = malloc([1]);

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Asizeof(int)

Bint

Cfree

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the type name instead of size.

Using free instead of malloc.

Passing a number without considering the size of the type.

The malloc function requires the size in bytes to allocate memory on the heap. Using sizeof(int) gives the correct size for an integer.

2fill in blank

medium

Complete the code to free the allocated memory correctly.

Compiler Design

free([1]);

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Asizeof(ptr)

BNULL

Cmalloc

Dptr

Attempts:

3 left

💡 Hint

Common Mistakes

Passing NULL to free.

Passing the size instead of the pointer.

Calling malloc inside free.

The free function releases the memory pointed to by ptr back to the heap.

3fill in blank

hard

Fix the error in the code to allocate memory for an array of 5 integers.

Compiler Design

ptr = malloc(5 [1] sizeof(int));

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A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of multiplication.

Using division or subtraction which are incorrect here.

Forgetting to multiply by the size of the type.

To allocate memory for 5 integers, multiply 5 by the size of an integer using the * operator.

4fill in blank

hard

Fill both blanks to correctly allocate and check memory allocation.

Compiler Design

ptr = malloc([1]);
if (ptr == [2]) {
    // handle error
}

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Asizeof(int) * 10

BNULL

C0

Dptr

Attempts:

3 left

💡 Hint

Common Mistakes

Not multiplying by the number of elements.

Checking pointer against 0 instead of NULL.

Using the pointer itself in the condition.

Memory is allocated for 10 integers. The pointer is checked against NULL to detect allocation failure.

5fill in blank

hard

Fill all three blanks to correctly allocate and initialize an array of 5 integers to zero.

Compiler Design

ptr = [1]([2], [3]);

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Acalloc

B5

Csizeof(int)

Dmalloc

Attempts:

3 left

💡 Hint

Common Mistakes

Using malloc, which does not initialize memory.

Confusing the arguments for calloc (num elements vs. total size).

Forgetting sizeof(int) for the element size.

calloc allocates memory for an array of 5 integers and initializes all bytes to zero. It takes the number of elements and the size of each element.