删除链接列表中项目的程序

实现

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;
struct node *prev = NULL;

//创建链接列表
void insert(int data) {
   // 为新节点分配内存;
   struct node *link = (struct node*) malloc(sizeof(struct node));

   link->data = data;
   link->next = NULL;

   // 如果 head 为空，则创建新列表
   if(head==NULL) {
      head = link;
      return;
   }

   current = head;
   
   // 移至列表末尾
   while(current->next!=NULL)
      current = current->next;
   
   // 在列表末尾插入链接
   current->next = link; 
}

void display() {
   struct node *ptr = head;

   printf("head] =>");
   //从头开始
   while(ptr != NULL) {        
      printf(" %d =>",ptr->data);
      ptr = ptr->next;
   }

   printf(" [null]
");
}

void remove_data(int data) {
   int pos = 0;
   
   if(head==NULL) {
      printf("Linked List not initialized");
      return;
   } 
    
   if(head->data == data) {
      if(head->next != NULL) {
         head = head->next;
         return;
      } else {
         head = NULL;
         printf("List is empty now");
         return;
      }
   } else if(head->data != data && head->next == NULL) {
      printf("%d not found in the list
", data);
      return;
   }

   //prev = head;
   current = head;
   
   while(current->next != NULL && current->data != data) {
      prev = current;
      current = current->next;
   }        

   if(current->data == data) {
      prev->next = prev->next->next;
      free(current);
   } else
      printf("%d not found in the list.", data);

}

int main() {
   insert(10);
   insert(20);
   insert(30);
   insert(1);
   insert(40);
   insert(56); 

   printf("Before Removal : ");
   display();
   remove_data(30);
   printf("After Removal  : ");
   display();
   
   return 0;
}

输出

程序的输出应为 −

Before Removal : [head] => 10 => 20 => 30 => 1 => 40 => 56 => [null]
After Removal  : [head] => 10 => 20 => 1 => 40 => 56 => [null]

linked_list_programs_in_c.html