搜索链接列表中的项目（Search an Item in Linked List）

实现 (Implementation)

该算法的实现如下 -

#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 find_data(int item) {
   int pos = 0;
   if(head == NULL) {
      printf("Linked List not initialized");
      return;
   } 
   current = head;
   while(current->next != head) {
      if(current->data == item) {
         printf("%d found at position %d\n", item, pos);
         return;
      }
      current = current->next;
      pos++;
   }
   if(current->data == item) {
      printf("%d found at position %d\n", item, pos);
      return;
   }
   printf("%d does not exist in the list", item);
}
int main() {
   insert(10);
   insert(20);
   insert(30);
   insert(1);
   insert(40);
   insert(56); 
   find_data(56);
   return 0;
}

输出 (Output)

该方案的产出应该是 -

56 found at position 5