C Runtime Error: Line 27: Char 29: runtime error: member access within null pointer of type 'struct ListNode' [solution.c]

This error occurs when trying to access a member of a null pointer. In this case, it seems that there is an attempt to access a member of a struct ListNode pointer that is currently null. \n\nTo fix this error, you need to ensure that the pointer is pointing to a valid object before accessing its members. You can do this by adding a null check before accessing the member. \n\nFor example, if you have a struct ListNode pointer called ptr and you want to access its value member, you can modify your code like this: \n\nc\nif (ptr != NULL) {\n int val = ptr->value; // Accessing the value member of ptr\n // rest of your code\n}\nelse {\n // handle the case when ptr is NULL\n}\n\n\nBy performing a null check, you can avoid the runtime error by only accessing the member if the pointer is not null.'}