剑指offer之C++语言实现链表(两种删除节点方式)-创新互联

1 问题

用C++语言实现链表

2 代码实现

#include 
#include 
using namespace std;
class List
{
public:
 List();
 ~List();
 List* createNode(int value);//创建节点
 bool insertNode(List *node);//插入节点
 void printList();//打印节点
 bool deleteNode(List *node);//删除节点不移动头节点
 bool deleteNode1(List *node);//删除节点移动头节点
 int listSize();//长度
 void printNode();//打印但前的value
 void freeList();//释放链表
private:
 int value;
 List *head;
 List *next;
};
bool List::deleteNode(List *node)
{
 if (node == NULL)
 {
 std:cout << "node is NULL" << std::endl; 
 return false;
 }
 if (head == NULL)
 {
 std::cout << "head is NULL" << std::endl; 
 return false;
 }
 //如果node等于head
 if (head == node)
 {
 head = head->next;
 }
 List *p = head;
 while (p->next != NULL)
 {
 if (p->next == node)
 {
  p->next = p->next->next;
  return true;
 }
 p = p->next;
 }
 return false; 
}
bool List::deleteNode1(List *node)
{
 if (node == NULL)
 {
 std:cout << "node is NULL" << std::endl; 
 return false;
 }
 if (head == NULL)
 {
 std::cout << "head is NULL" << std::endl; 
 return false;
 }
 //如果node等于head
 if (head == node)
 {
 head = head->next;
 }
 List *p = head;
 while (head->next != NULL)
 {
 if (head->next == node)
 {
  head->next = head->next->next;
  std::cout << "delete node success head->value" << head->value << std::endl;
  //这里要记得把头节点的指针移动最后还原,这里的头节点是保存在这个类里面,改变了就是改变了
  //如果这里是把head作为参数传递,最后head会被销毁那么不需要移动头指针
  head = p;
  return true;
 }
 //注意,这里由于head是成员变量,改变了就是改变了,所以需要最后重新指定
 head = head->next;
 }
 std::cout << "delete node fail head->value" << head->value << std::endl;
 //这里要记得把头节点的指针移动最后还原,这里的头节点是保存在这个类里面,改变了就是改变了
 //如果这里是把head作为参数传递,最后head会被销毁那么不需要移动头指针
 head = p;
 return false; 
}
List::List()
{
 value = 0;
 head = NULL;
 next = NULL;
}
List::~List()
{
 delete head;
 delete next;
}
List* List::createNode(int value)
{
 List *list = NULL;
 list = new List();
 if (list)
 {
 list->value = value;
 return list; 
 }
 return NULL;
}
bool List::insertNode(List *node)
{
 node->next = head;
 head = node;
 return true; 
}
void List::printList()
{ if (head == NULL)
 {
 std::cout << "head is NULL" << std::endl;
 return;
 }
 List *p = head;
 while (p != NULL)
 {
 std::cout << p->value << std::endl; 
 p = p->next;
 }
 return; 
}
void List::printNode()
{
 std::cout << value << std::endl; 
}
int List::listSize()
{
 if (head == NULL)
 {
 std::cout << "head is NULL" << std::endl;
 return 0; 
 }
 int len = 0;
 List *p = head;
 while (p != NULL)
 {
 p = p->next;
 ++len;
 }
 return len;
}
void List::freeList()
{
 if (head == NULL)
 {
 std::cout << "head is NULL" << std::endl;
 return; 
 }
 List *p;
 while (head != NULL)
 {
 p = head;
 head = head->next;
 free(p);
 }
}
int main()
{
 List list;
 List *list1 = list.createNode(5);
 list.insertNode(list1);
 List *list2 = list.createNode(6);
 list.insertNode(list2);
 List *list3 = list.createNode(1);
 list.insertNode(list3);
 List *list4 = list.createNode(3);
 list.insertNode(list4);
 List *list5 = list.createNode(2);
 list.insertNode(list5);
 list.printList();
 std::cout << "list size is " << list.listSize() << std::endl;
 std::cout << "-----------开始删除节点值为3的节点" << std::endl;
 list.deleteNode1(list4);
 list.printList();
 std::cout << "list size is " << list.listSize() << std::endl;
 list.freeList();
 list.printList();
 return 0; 
}

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