Segmentation fault in passing pointer to a linked list - c++

Question

Hello fellow programmers, the below code gives segmentation fault. This code aims to insert an element at the end of a linked list. I tried using print statements to debug it. I think the error is in passing the linked list pointer to insert() function. Please tell me how can I correct it. Thanks in advance.
Below is the code:
#include <iostream>
using namespace std;
class node {
public:
int data;
node *next;
node(int data) {
this->data = data;
this->next = NULL;
}
};
class linked_list {
public:
node *head;
linked_list() {
this->head = NULL;
}
};
void insert(node **head, int data);
void print(linked_list *L);
int main() {
int N;
linked_list *A = new linked_list();
cout << "N: ";
cin >> N;
for(int i=0; i<=N-1; i++) {
int t;
cin >> t;
insert(&(A->head), t);
}
print(A);
return 0;
}
void insert(node **head, int data) {
node *temp = new node(data);
if(*head == NULL) {
*head = temp;
return;
} else {
node *t = *head;
while(t->next != NULL) {
t=t->next;
}
t->next = temp;
return;
}
}
void print(linked_list *L) {
node * t = L->head;
while(t!=NULL) {
cout << t->data << " ";
t = t->next;
}
return;
}

Answer 1

main.cpp:42:14: error: using the result of an assignment as a
condition without parentheses [-Werror,-Wparentheses]
if(*head = NULL) {
~~~~~~^~~~~~
main.cpp:42:14: note: place parentheses around the assignment to
silence this warning
if(*head = NULL) {
^
( )
main.cpp:42:14: note: use '==' to turn this assignment into an
equality comparison
if(*head = NULL) {
^
==
1 error generated.
You're using assignment where you intended to do a comparison.