free in c

Free in C

In C, the free function is used to deallocate memory that was previously allocated using the malloc, calloc, or realloc functions. Here's a step-by-step explanation of how the free function works:

1. Check if the pointer is not NULL: Before calling free, it's important to ensure that the pointer being passed to free is not NULL. Attempting to free a NULL pointer can lead to undefined behavior.

2. Release the allocated memory: When free is called with a valid pointer, it releases the memory block pointed to by the pointer, making it available for further allocation.

3. Do not use the pointer after freeing: After calling free, the pointer should not be dereferenced. Doing so can lead to undefined behavior.

4. Example: Here's an example of using the free function:

c int ptr = (int )malloc(10 * sizeof(int)); // Allocate memory // Check if allocation was successful if (ptr != NULL) { // Use the allocated memory // ... // Free the allocated memory when it's no longer needed free(ptr); }

After calling free(ptr), the memory previously allocated for ptr is deallocated.