C语言实现链表

大作业水平...

#include<stdio.h>
#include<stdlib.h>

struct node{
    struct node* next;
    int c;
};

struct node* init_node(int input)
{
    struct node* p;
    p = malloc(sizeof(struct node));
    p->c = input;
    return p;
}

void insert_node(struct node *head, int new)
{
    struct node *temp = (struct node*)(malloc(sizeof(struct node)));
//    struct node *temp;
    while(head->next != NULL)
        head = head->next;
    head->next = temp;
    temp->c = new;
    temp->next = NULL;
}

void display_list(struct node* head){
    if(head == NULL)
    {
      printf("error.\n");
      return;
    }
    struct node *p = head;
    while(p->next != NULL)
    {
        printf("%d ",p->c);
        p = p->next;
    }
    printf("%d ", p->c);
    printf("NULL\n");
}

void destroy_list(struct node *head)
{
    if (NULL != head) {
        destroy_list(head->next);
//        free(head->c);
        free(head);
        printf("destroy a list...\n");
    }
}

struct node* copy_list(struct node* head)
{
  struct node* p = (struct node*)(malloc(sizeof(struct node)));
  p->next = NULL;
  if(head == NULL)
  {
    printf("head is NULL.\n");
    return;
  }
  p->c = head->c;
  head = head->next;
  while(head != NULL)
  {
    printf("copying... head->c: %d\n", head->c);
    insert_node(p, head->c);
    head = head->next;
  }
//  insert_node(p, head->c);
  return p;
}

struct node* reverse_list(struct node* head)
{
  struct node* p;
  struct node* t;
  p = (struct node*)(malloc(sizeof(struct node)));
  p->c = head->c;
  p->next = NULL;
  while(head->next != NULL)
  {
    head = head->next;
    t = p;
    p = (struct node*)(malloc(sizeof(struct node)));
    p->next = t;
    p->c = head->c;
  }
  return p;
}

int main(int argc, char** argv)
{
    struct node *head = init_node(1);
    long long i;
    insert_node(head, 2);
    insert_node(head, 3);
    insert_node(head, 4);
    insert_node(head, 5);
    insert_node(head, 6);
    insert_node(head, 7);
    display_list(head);
    struct node* copy = copy_list(head);
    printf("copy done.\n");
    struct node* reve = reverse_list(head);
    display_list(reve);
    for (i = 0; i < 0x1000000; i++) reve = reverse_list(head);
    display_list(reve);
    display_list(copy);
    destroy_list(head);
    destroy_list(copy);
    return 0;
}