C++模板类实现链表

简单的实现了增删元素、输出链表元素和大小的功能

#include <vector>
#include <string>
#include <iostream>
#include <cstdlib>
using std::string;

template <class T>
class List
{
private:
    struct listNode
    {
        listNode *next;
        T val;
        listNode(T val, listNode* next = nullptr) : val(val), next(next) {};
    };
    listNode* head;
    int size;
public:
    List() : head(nullptr), size(0) {}
    void add(T);
    void print();
    int getSize(){return size;};
    void remove(T const&);
};

template <class T>
void List<T>::add(T elem)
{
    if(head == nullptr)
        head = new listNode(elem);
    else
    {
        listNode* cur = head;
        while(cur->next != nullptr)
            cur = cur->next;
        cur->next = new listNode(elem);
    }
    ++size;
}

template <class T>
void List<T>::remove(T const& elem)
{
    if(head == nullptr)
    {
        std::cout << "链表为空！" << std::endl;
        return;
    }
    if(head->val == elem)
    {
        head = head->next;
        --size;
        return;
    }
    listNode* cur = head;
    while(cur->next && cur->next->val != elem)
        cur = cur->next;
    if(cur->next == nullptr)
    {
        std::cout << elem << "不在链表内！" << std::endl;
        return;
    }
    cur->next = cur->next->next;
    --size;
    return;
}

template <class T>
void List<T>::print()
{
    if(head == nullptr)
    {
        std::cout << "链表为空！" << std::endl;
        return;
    }
    listNode* cur = head;
    while(cur != nullptr)
    {
        std::cout << cur->val << " -> ";
        cur = cur->next;
    }
    std::cout << std::endl;
}

int main()
{
    List<string> a;
    a.add("def");
    a.add("abc");
    a.add("anbd");
    std::cout << "链表的长度为：" << a.getSize() << std::endl;
    a.remove("defa");
    a.print();
    return 0;
}