C示例查找循环链接列表大小的程序

#include <stdio.h>

#include <stdlib.h>



struct node {

   int data;

   struct node *next;

};



struct node *head = NULL;

struct node *current = NULL;



//insert link at the first location

void insert(int data) {

   // Allocate memory for new node;

   struct node *link = (struct node*) malloc(sizeof(struct node));



   link->data = data;

   link->next = NULL;



   // If head is empty, create new list

   if(head==NULL) {

      head = link;

      head->next = link;

      return;

   }



   current = head;



   // move to the end of the list

   while(current->next != head)

      current = current->next;



   // Insert link at the end of the list

   current->next = link;



   // Link the last node back to head

   link->next = head;



}



//display the list

void list_size(struct node *list) {

   int size = 0;



   if(head==NULL) {

      printf("List size : %d ", size);

      return;

   }



   current = head;

   size = 1;



   while(current->next != head) {

      current = current->next;

      size++;

   }



   printf("List size : %d ", size);   

}



int main() {

   insert(10);

   insert(20);

   insert(30);

   insert(1);

   insert(40);

   insert(56);



   list_size(head);



   return 0;

}