Quiz for Dynamic memory allocation free

Q1: What is the purpose of the free() function in C?

A. To allocate memory B. To deallocate previously allocated memory C. To reallocate memory D. To initialize memory to zero

Q2: What happens if free() is not called for dynamically allocated memory?

A. The program will crash immediately B. Memory leak may occur C. The memory will be automatically freed at once D. It resets all memory values to zero

Q3: Can free() be called on a NULL pointer?

A. Yes, it has no effect B. No, it will cause an error C. Yes, but only for malloc() D. Yes, but only for calloc()

Q4: What is undefined behavior with free()?

A. Freeing memory twice B. Freeing a NULL pointer C. Freeing memory allocated by malloc() D. Not freeing memory

Q5: Which function should be paired with malloc() for memory management?

A. calloc() B. realloc() C. free() D. alloc()

Q6: After calling free() on a pointer, what should be done to avoid dangling pointer issues?

A. Set pointer to NULL B. Call malloc() again C. Call realloc() D. Leave it as it is

Q7: Is it valid to free memory allocated on the stack?

A. Yes, for any variable B. No, only heap memory should be freed C. Yes, for global variables D. Yes, for static variables

Q8: What happens if you call free() on memory not allocated by malloc/calloc/realloc?

A. Nothing happens B. It causes undefined behavior C. It reallocates memory D. It frees all heap memory

Q9: Which statement is correct regarding free()?

A. It can be used with automatic variables B. It can be used with dynamically allocated variables C. It resets memory to zero D. It doubles the allocated memory

Q10: If free() is called, what happens to the memory?

A. It becomes available for future allocations B. It is immediately reassigned C. It is moved to stack D. It is permanently deleted from system

Q11: Can free() be used to release part of allocated memory?

A. Yes, always B. No, only entire block can be freed C. Yes, using pointer arithmetic D. Yes, using realloc()

Q12: What is the effect of freeing memory twice?

A. Memory is freed twice successfully B. Causes undefined behavior C. Increases heap size D. Frees only once

Q13: What happens to a pointer variable after calling free()?

A. It still points to the freed memory B. It points to NULL automatically C. It points to a random location D. It points to stack memory

Q14: Which is the correct syntax to free memory pointed by ptr?

A. delete ptr; B. free(&ptr); C. free(ptr); D. release(ptr);

Q15: When should free() be used?

A. For global variables B. For local variables C. For dynamically allocated memory D. For static memory

Q16: What does free() do to the content of memory?

A. Deletes it permanently B. Leaves it unchanged C. Sets it to zero D. Randomizes it

Q17: Which header file is required for free()?

A. stdlib.h B. stdio.h C. malloc.h D. memory.h

Q18: Can free() release memory allocated with realloc()?

A. Yes B. No C. Only if size > 0 D. Only for NULL realloc

Q19: If malloc() fails, should free() be called?

A. Yes B. No C. Only if pointer is not NULL D. Only if pointer is static

Q20: What will happen if free() is called on an already freed pointer?

A. Memory will be freed again B. Undefined behavior occurs C. It sets pointer to zero D. Nothing happens