C | Dynamic Memory Allocation | Question 3
(A) May not work
(B) Works and prints 6
Explanation: The program is not valid. Try replacing “int *p;” with “int *p = NULL;” and it will try to dereference a null pointer.
This is because fun() makes a copy of the pointer, so when malloc() is called, it is setting the copied pointer to the memory location, not p. p is pointing to random memory before and after the call to fun(), and when you dereference it, it will crash.
If you want to add memory to a pointer from a function, you need to pass the address of the pointer (ie. double pointer).