这是一个利用类的继承和实现压栈及出栈，在VC 6中能过编译无语法错误，但不能显示栈链及出栈，这是很典型错误，请大家一起讨论

/* ***********
node.h
*************/


#include <iostream>
using namespace std;
class node
{
    friend class linklist;
    friend class stack;
public:
    node();
    node(node &n);
    node(int i,char c='0');
    node(int i,char c,node *p,node *n);
    ~node();
private:
    int idata;

    char cdata;

    node *prior;

    node *next;

};
node::node()
{
    cout <<"Node constructor is running..." <<endl;

    idata=0;
    cdata='0';
    prior=NULL;

    next=NULL;

}
node::node(int i,char c)
{
    cout <<"Node constructor is running..." <<endl;
    idata=i;
    cdata=c;
    prior=NULL;
    next=NULL;
}
node::node(int i,char c,node *p,node *n)
{
    cout <<"Node constructor is running..." <<endl;
    idata=i;
    cdata=c;
    prior=p;
    next=n;
}
node::node(node &n)
{
    idata=n.idata;
    cdata=n.cdata;
    prior=n.prior;
    next=n.next;
}
node::~node()
{
    cout <<"Node destructor is running..." <<endl;
}

/***************
linklist.h
****************/
#include "node.h"
#include <iostream>
using namespace std;
class linklist
{
public:
    linklist(int i=0,char c='0');
    linklist(linklist &l);
    ~linklist();
    bool locate(int i);
    bool locate(char c);
    bool insert(int i=0,char c='0');
    bool Delete();
    void show();
    void destroy();
protected:
    node head;
    node * pcurrent;
};
linklist::linklist(int i,char c):head(i,c)
{
    cout<<"Linklist constructor is running..."<<endl;
    pcurrent=&head;
}
linklist::linklist(linklist &l):head(l.head)
{
    cout<<"Linklist Deep cloner running..." <<endl;
    pcurrent=&head;
    node * ptemp1=l.head.next;
    while(ptemp1!=NULL)
    {
        node * ptemp2=new node(ptemp1->idata,ptemp1->cdata,pcurrent,NULL);
        pcurrent->next=ptemp2;
        pcurrent=pcurrent->next;
        ptemp1=ptemp1->next;
    }
}
linklist::~linklist()
{
    cout<<"Linklist destructor is running..."<<endl;
    destroy();
}
bool linklist::locate(int i)
{
    node * ptemp=&head;
    while(ptemp!=NULL)
    {
        if(ptemp->idata==i)
        {
            pcurrent=ptemp;
            return true;
        }
        ptemp=ptemp->next;
    }
    return false;
}
bool linklist::locate(char c)
{
    node * ptemp=&head;
    while(ptemp!=NULL)
    {
        if(ptemp->cdata==c)
        {
            pcurrent=ptemp;
            return true;
        }
        ptemp=ptemp->next;
    }
    return false;
}
bool linklist::insert(int i,char c)
{
    if(pcurrent!=NULL)
    {
        node * temp=new node(i,c,pcurrent,pcurrent->next);
        if (pcurrent->next!=NULL)
        {
            pcurrent->next->prior=temp;
        }
        pcurrent->next=temp;
        return true;
    }
    else
    {
        return false;
    }
}
bool linklist::Delete()
{
    if(pcurrent!=NULL && pcurrent!=&head)
    {
        node * temp=pcurrent;
        if (temp->next!=NULL)
        {
            temp->next->prior=pcurrent->prior;
        }
        temp->prior->next=pcurrent->next;
        pcurrent=temp->prior;
        delete temp;
        return true;
    }
    else
    {
        return false;
    }
}
void linklist::show()
{
    node * ptemp=&head;
    while (ptemp!=NULL)
    {
        cout <<ptemp->idata <<'\t' <<ptemp->cdata <<endl;
        ptemp=ptemp->next;
    }
}
void linklist::destroy()
{
    node * ptemp1=head.next;
    while (ptemp1!=NULL)
    {
        node * ptemp2=ptemp1->next;
        delete ptemp1;
        ptemp1=ptemp2;
    }
    head.next=NULL;
}

/***************
stack.h
****************/

#include "linklist.h"
class stack:private linklist
{
public:
    bool push(int i,char c);//
    bool pop(int &i,char &c); //
    void show();
};
bool stack::push(int i,char c)
{
    while(pcurrent->next != NULL)
        pcurrent = pcurrent->next;
    return insert(i,c);  //
}
bool stack::pop(int &i,char &c) //
{
    while (pcurrent->next != NULL)
        pcurrent = pcurrent ->next;
    i = pcurrent->idata; //
    c = pcurrent->cdata; //
    return Delete();  //
}
void stack::show()
{
    show();
}

/*****************
main.cppp
******************/


#include <iostream>
#include "stack.h"
int main()
{
    stack ss;
    int i,j;
    char c;
    for (j=0;j<3;j++)
    {
        cout <<"请输入一个数字和一个字母：" <<endl;
        cin >>i >>c;
        if (ss.push(i,c))
        {
            cout <<"压栈成功！" <<endl;
        }
    } //为何程序在这里 就结束了，不往下执行了！是那出错了！！请大家一起来讨论！！！
    ss.show();  
    while (ss.pop(i,c))
    {
        cout <<"退栈数据为i=" <<i <<" c=" <<c <<endl;
    }
    return 0;      

}