C++实现简单的单链表

#pragma once
#include <iostream>
using namespace std;

class ListEx
{
private:
struct Node
{
Node* next;
int data;
Node(const Node& node): data(node.data), next(nullptr) {}
Node(const T& d): data(d), next(nullptr) {}
};

private:
Node* head;
int n; //索引

public:
ListEx(): head(nullptr), n(0) {}
Node* getp(int pos)
{
if (pos < 0 || pos > n)
{
return nullptr;
}

if (pos == 0)
{
return head;
}

Node* p = head;

for (int i = 1; i < pos; i++)
{
p = p->next;
}

return p->next;
}

void travel()
{
Node* p = head;

if (p == nullptr)
{
return;
}

p = p->next;

while (p)
{
cout << p->data << "\t" << endl;
p = p->next;
}
}

void insert(int d, int pos = -1)
{
if (head == nullptr)
{
head = new Node(0);
Node* p = new Node(d);
head->next = p;
p->next = nullptr;
}
//添加到最后
else if (pos < 0 || pos > n)
{
Node* p = getp(n);
Node* node = new Node(d);
p->next = node;
node = nullptr;
}
//添加到pos位置
else
{
Node* node = new Node(d);

Node* p = getp(n - 1);
Node* q = p->next;
p->next = node;
node->next = q;
}

++n;
}

//从pos开始查找data 为d的元素,默认从0开始
int find(int d, int pos = 0)
{
Node* p = getp(pos);

if (p == nullptr)
{
return -1;
}

while (p)
{
if (p->data == d)
{
return pos;
}

pos++;
p = p->next;
}

return -1;
}

//从pos开始删除data为d的元素
bool erase(int d, int pos = 0)
{
int nIndex = find(d, pos);

if (nIndex == -1)
{
return false;
}

Node* p = getp(nIndex - 1);
Node* q = getp(nIndex);

if (p == nullptr)
{
return false;
}

p->next = q->next;
delete q;
return true;
}

};