[Solved] Question from challenges

Question

What is the problem with following code?
int *p = (int*)malloc(sizeof(int)) ;
p = NULL;
free(p) ;

-Compiler error: free can't be applied on NULL pointer.

✔️There is a memory leak. (correct answer)

-p becomes a dangling pointer.

-The program will crash as a NULL pointer is passed to free()

The question is why would this cause memory leak?

Answer 1

The program allocates memory but can never free it because p is set to NULL and therefore the address of the allocated memory is lost.
This is called a memory leak because if this e.g. would be done in a loop or with larger memory blocks a program would claim more and more memory without freeing it until eventually no more memory is available anymore.

Answer 2

Nicely explained, yes, makes total sense now. Thanks Aaron Eberhardt 👌