Dynamic Memory: new and delete

Heap Allocation

Local variables live on the stack and are freed automatically. new allocates on the heap — it persists until you delete it:

int* p = new int(42);
cout << *p;    // 42
delete p;       // free the memory — ALWAYS do this!
p = nullptr;    // good practice

int* arr = new int[10];
arr[0] = 5;
delete[] arr;   // note: delete[] for arrays, not delete

Common pitfalls

• Memory leak — allocate but forget to delete
• Double delete — calling delete twice → crash
• Dangling pointer — using a pointer after deleting it

In modern C++, prefer unique_ptr / shared_ptr (covered in Chapter 9) over raw new/delete.

Your Task

Write createArray(int size, int fillVal) that allocates a heap array of size ints, fills each with fillVal, and returns the pointer.