有/无头节点的单链表的创建(尾插法)

#include <iostream>

typedef struct node
{
int data;
struct node *next;
} NODE;

// 采用尾插法，创建带头节点的单链表
NODE *create_end_1(int arr[], int len)
{
NODE *head = (NODE *)malloc(sizeof(NODE *));
head->next = NULL; // 1
NODE *end = head;

for (int i = 0; i < len; i++) {  // 2
NODE *p =  (NODE *)malloc(sizeof(NODE *));
p->data = arr[i];

end->next = p;
end = p;
}
end->next = NULL;

return head;
}

// 采用尾插法，创建一个没有头节点的单链表
NODE *create_end_2(int arr[], int len)
{
NODE *head = (NODE *)malloc(sizeof(NODE *));
head->data = arr[0]; // 1
NODE *end = head;

for (int i = 1; i < len; i++) { // 2
NODE *p =  (NODE *)malloc(sizeof(NODE *)); // 也可用 new NODE();
p->data = arr[i];

end->next = p;
end = p;
}
end->next = NULL;

return head;
}

// 此方法适用于不带头节点的单链表的打印，对于带头节点的单链表要稍作处理。
void print(NODE *head)
{
if (head == NULL) return;

while (head != NULL) {
printf("%d\n",head->data);
head = head->next;
}
}

int main(int argc, const char * argv[]) {

int arr[] = {1,2,3,4,5,6,7};
int len = sizeof(arr)/sizeof(int);

// 带头节点的单链表
NODE *head1 = create_end_1(arr, len);
NODE *first = head1->next;
print(first);

printf("----------------------\n");

// 不带头节点的单链表
NODE *head2 = create_end_2(arr, len);
print(head2);

return 0;
}