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Memory Management · medium

2. Dynamic Memory: malloc, calloc, realloc, and free

Heap allocations and manual lifetime control.

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Stack memory is local to functions; heap memory is allocated manually via `malloc` / `calloc` and must be freed with `free`. Failing to free causes memory leaks; using freed pointers causes Use-After-Free vulnerabilities.

c
int *arr = (int *)malloc(10 * sizeof(int));
if (!arr) { /* handle out of memory */ }
free(arr);
arr = NULL;

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Check your understanding

1. How does calloc differ from malloc?
calloc zero-initializes allocated memory bytes; malloc leaves memory uninitializedcalloc allocates stack memorymalloc is type-safecalloc cannot be freed
2. What is a 'Dangling Pointer' in C?
A pointer referencing memory that has already been freedA pointer set to NULLA stack overflow errorA void pointer

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