Duplicate an array

Challenge

Make an independent heap copy of an array, so the caller gets its own buffer to modify and free.

Task

Implement int *dup_array(const int *a, int n) that returns a freshly malloc-ed copy of the first n elements of a. No main — the grader calls it and frees the result.

Input

a — pointer to the source int array. n — the number of elements to copy.

Output

On success, returns a new malloc-ed int* (distinct from a) holding a copy of the n elements. The caller frees it. Return NULL for invalid/empty requests or allocation failure, as specified in the contract below.

Example

int src[] = {3, 1, 4, 1, 5};
dup_array(src, 5)   ->   {3, 1, 4, 1, 5}   (a separate block, src != copy)

Rules

• The copy is a separate heap block; the caller frees it.

Why this matters

Drill: practice one contract before combining it with other skills.

Input format

a — pointer to the source int array. n — the number of elements to copy.

Output format

On success, returns a new malloc-ed int* (distinct from a) holding a copy of the n elements. The caller frees it. Return NULL for invalid/empty requests or allocation failure, as specified in the contract below.

Constraints

For n <= 0, NULL source, or unrepresentable byte size return NULL. Otherwise read n live source ints and return a separately allocated copy. Failure returns NULL; input is never freed or modified; caller frees the copy.

Starter code

#include <stdlib.h>
#include <string.h>

int *dup_array(const int *a, int n) {
    /* TODO */
    return NULL;
}

Common mistakes

Returning the original array or copying n bytes instead of n ints.

Edge cases to handle

One element, repeated and negative values, mutation of the copy leaves the source unchanged, empty/invalid request, allocation failure.

Up next

• Allocate, use, free