C++实现单向链表

****************************IntSLList.h*****************************/
#ifndef _INTSLLIST_H_
#define _INTSLLIST_H_


class IntSLLNode{
public:
        IntSLLNode(){next = 0;}
        IntSLLNode(int el, IntSLLNode *ptr = 0){
                info = el; next = ptr;
        }
        int info;
        IntSLLNode *next;
};

class IntSLList{
public:
        IntSLList(){head = tail = 0;} 
        ~IntSLList();
        int isEmpty(){return head == 0;} 
        
        void addToHead(int);
        void addToTail(int);

        void deleteNode(int);
        bool isInList(int)const;
        void print()const;
private:
        IntSLLNode *head,*tail;
};

#endif

/**************************IntSLList.cpp****************************/
#include "IntSLList.h"
#include <iostream>

IntSLList::~IntSLList()
{
        for(IntSLLNode *p; !isEmpty();){     
                p = head->next;
                delete head;
                head = p;
        }
}

void IntSLList::addToHead(int el) 
{
        head = new IntSLLNode(el);
        if(0 == tail)
                tail = head;
}

void IntSLList::addToTail(int el) 
{
        if(tail != 0){ 
                tail->next = new IntSLLNode(el);
                tail = tail->next;
        }
        else{
                head = tail = new IntSLLNode(el);
        }
}

int IntSLList::deleteFromHead()
{
        int el = head->info;
        IntSLLNode *tmp = head;
        if(head == tail)
                head = tail = 0;
        else
                head = head->next;
        delete tmp;
        return el;
}

int IntSLList::deleteFromTail()
{
        int el = tail->info;
        if(head == tail){
                delete head;
                head = tail = 0;
        }
        else{
                IntSLLNode *tmp;
                for(tmp = head; tmp->next != tail; tmp = tmp->next);
                delete tail;
                tail = tmp;
                tmp->next = 0;
        }
        return el;
}

void IntSLList::deleteNode(int el)
{
        if(head != 0)
                if(el == head->info && head == tail){
                        delete head;
                        head = tail = 0;
                }
                else if(el == head->info){
                        IntSLLNode *tmp;
                        head = head->next;
                        delete tmp;
                }
                else{
                        IntSLLNode *pred,*tmp;
                        for(pred = head, tmp = head->next;
                            tmp !=0 && !(tmp->info == el);
                            pred = pred->next, tmp = tmp->next);
                        if(tmp != 0){
                                pred->next = tmp->next;
                                if(tmp == tail)
                                        tail = pred;
                                delete tmp;
                        }
                }
}

bool IntSLList::isInList(int el)const
{
        IntSLLNode *tmp;
        for(tmp = head; tmp !=0 && tmp->info != el; tmp = tmp->next);
        return tmp != 0;
}

void IntSLList::print()const
{
        IntSLLNode *tmp;
        for(tmp = head; tmp != 0; tmp = tmp->next){
                std::cout << tmp->info << ' ';
        }
        std::cout << std::endl;
}