类模板

类模板

以一个链表类模板作为例子

 

//Test1.h
#include<iostream>
using namespace std;
template<typename Type>
class List;
template<typename Type>//模板类作为友元类则得友元前声明
class Listnode
{
    friend class List<Type>;
private:
    Type a;
    Listnode<Type> *next;
public:
    Listnode():a(Type()),next(NULL)
    {}
    Listnode(Type _a, Listnode<Type> *_next=NULL):a(_a),next(_next)
    {}
    ~Listnode(){}
};
template<typename Type>
class List
{
private:
    Listnode<Type> *first;
    Listnode<Type> *last;
    size_t size;
public:
    List();
    bool push_back(Type t);
    bool push_front(Type t);
    void print()const;
    bool delate(Type t);
};
////////////////////////////////////////////////////
template<typename Type>//类模板的方法在外部实现的时候和函数模板基本相同，
bool List<Type>::push_front(Type t)//都要使用template关键字,还有得在 类名后加上<模板参数>
{
    Listnode<Type> *tmp = (Listnode<Type>*)malloc(sizeof(Listnode<Type>));
    if(tmp != NULL)
    {
        tmp->a = t;
        if(this->size == 0)
        {
            this->first->next = tmp;
            tmp->next = NULL;
            this->last = tmp;
        }
        else
        {
            tmp->next = this->first->next;
            this->first->next = tmp;
        }
        ++this->size;
        return true;
    }
    else
        return false;
}
template<typename Type>
bool List<Type>::delate(Type t)
{
    if(this->first->next != NULL)
    {
        Listnode<Type> *p = this->first->next;
        Listnode<Type> *q = this->first;
        while(p != NULL)
        {
            if(p->a == t)
            {
                if(p->next != NULL)
                {
                    q->next = p->next;
                    p->next = NULL;
                }
                else
                {
                    q->next = NULL;
                    this->last = q;
                }
                --this->size;
            }
            else
            {
                q = p;
                p = p->next;
                continue;
            }
            p = q->next;
        }
    }
    return true;
}
template<typename Type>
List<Type>::List()
{
    first = last = (Listnode<Type>*)malloc(sizeof(Listnode<Type>));
    last->next = NULL;
    this->size = 0;
}
template<typename Type>
bool List<Type>::push_back(Type t)
{
    Listnode<Type> *tmp = (Listnode<Type>*)malloc(sizeof(Listnode<Type>));
    if(tmp == NULL)
        return false;
    tmp->a = t;
    tmp->next = NULL;
    this->last->next = tmp;
    this->last = tmp;
    ++this->size;
    return true;
}
template<typename Type>
void List<Type>::print()const
{
    if(this->size != 0)
    {
        Listnode<Type> *p = this->first->next;

        while(p != NULL)
        {
            cout<<p->a<<"->";
            p = p->next;
        }
        cout<<"NUL."<<endl;
    }
    else
    {
        cout<<"List size is zero."<<endl;
    }
    return;
}

 实现了前插、尾插、print 和删除功能

//Test.cpp
#include"Test1.h"
void main()
{
    List<char> char_list;　　//<>内填入什么类型，就会构造那种类型的链表对象
    for(int i=65; i<=69; ++i)
    {
        char_list.push_back(i);
    }
    char_list.print();
    char_list.delate('B');
    char_list.print();
    List<int> int_list;
    for(int i=65; i<=69; ++i)
    {
        int_list.push_front(i);
    }
    int_list.delate(128);
    int_list.print();
}

 运行结果