Unusual Segmentation Fault - c++

Question

I was trying to delete alternate nodes in a linklist. I observed a strange behaviour.
void delete_alternate_node_LinkedList(Node *head) {
Node *prev = head;
Node *curr = head->next;
while (prev != NULL and curr != NULL) {
prev->next = curr->next;
free(curr);
prev = prev->next;
if (prev != NULL) {
curr = prev->next;
}
}
}
This code works fine except the head being nullptr when I use free to delicate or intentionally keep a memory leak but if I change the line free(curr) with delete curr, I get a segmentation fault.
Can anyone explain me the reason?
Here are the boilerplate codes
class Node {
public:
int data;
Node * next;
Node(int data){
this -> data = data;
this -> next = NULL;
}
~Node() {
if(next) {
delete next;
}
}
};
Node* takeinput() {
int data;
cin >> data;
Node *head = NULL, *tail = NULL;
while(data != -1){
Node *newNode = new Node(data);
if(head == NULL) {
head = newNode;
tail = newNode;
}
else{
tail -> next = newNode;
tail = newNode;
}
cin >> data;
}
return head;
}
void print(Node *head) {
Node *temp = head;
while(temp != NULL) {
cout << temp -> data << " ";
temp = temp -> next;
}
cout << endl;
}

Answer 1

Your destructor has a problem
Let's assume
A->B->C->D->nullptr
Now when you delete B it invokes destructor (if you use free it won't).
it will delete recursively C (which in turn delete D) and ..... till the end
so in next iteration you are holding on to a dangling pointer (C) and getting the segfault when you are trying to derefence it.