一个栈的类。。运行时出现问题。。。求解

[fengyuewuh]

#ifndef STACK_H
#define STACK_H

class stack{
class link;
link* head;
public:
stack();
~stack();
void push(void* dat);
void* pop();
void* peek();
};

#endif

#include "stack.h"
#include <iostream>
using namespace std;

class stack::link{
public:
void* data;
link* next;
link(void* dat,link* nxt);
~link();
};

stack::link::link(void* dat,link* nxt)
{ data=dat;
next=nxt;
}

stack::link::~link()
{
}

stack::stack()
{ head=0;
}

stack::~stack()
{
}

void stack::push(void* dat)
{head=new link(dat,head);
}

void* stack::pop()
{if(head==0){
cout<<"stack is empty"<<endl;
return 0;}

void* result=head->data;
link* oldhead;
oldhead=head;
head=head->next;
delete oldhead;
return result;
}



void* stack::peek()
{ if(head==0){
cout<<"stack is empty"<<endl;
return 0;}

return head->data;
}


#include "stack.h"
#include <iostream>
using namespace std;
int main()
{stack* s1;
int i=1;
s1->push(&i);
s1->pop();
return 0;
}
运行时出现遇到问题需要关闭的对话框。。。应该是new的问题。。可是怎么改都不对。。请问问题出在哪儿，该如何改正哈？？？？

[K行天下]

放到一个文件：（要不你将那个link类放到头文件，link类的实现放到实现文件）

#include <iostream>
using namespace std;
#ifndef STACK_H
#define STACK_H

class stack
{
    class link;
    link* head;
public:
    stack();
    ~stack();
    void push(void* dat);
    void* pop();
    void* peek();
};

#endif

//#include "stack.h"
//#include <iostream>
//using namespace std;

class stack::link
{
    public:
    void* data;
    link* next;
    link(void* dat,link* nxt);
    ~link();
};

stack::link::link(void* dat,link* nxt)
{ data=dat;
  next=nxt;
}

stack::link::~link()
{
}

stack::stack()
{ head=0;
}

stack::~stack()
{
}

void stack::push(void* dat)
{
    head=new link(dat,head);
}

void* stack::pop()
{
    if(head==0)
    {
        cout <<"stack is empty" <<endl;
        return 0;
    }

    void* result=head->data;
    cout<<*(int*)head->data<<endl;
    link* oldhead;
    oldhead=head;
    head=head->next;
    delete oldhead;
    return result;
}


void* stack::peek()
{ if(head==0){
  cout <<"stack is empty" <<endl;
  return 0;}

return head->data;
}


//#include "stack.h"

int main()
{
    stack* s1;
    int i=1,j=2;
    s1->push(&i);
    s1->push(&j);
    s1->pop();
    s1->pop();
    s1->pop();
    return 0;
}

[sys0002]

int main()
{
    stack* s1 = new stack;

    int i = 1;
    s1->push(&i);
    s1->pop();

    return 0;
} 

[rock_HX]

最近好多人发帖重复...

[lzr4304061988012]

int main() 
{
	stack * s1=new stack; 

	int i=1; 

	s1->push(&i); 

	s1->pop(); 
  
	return 0; 
} 

[zhkefa]

重复的，，

[帅得不敢出门]

[Quote=引用 2 楼 sys0002 的回复:]
C/C++ code
int main()
{
stack* s1 = new stack;

int i = 1;
s1->push(&i);
s1->pop();

return 0;
}
[/Quote]
up stack* s1;
指针未初始化 就使用了 所以错误了

[chenzhp]

stack* s1 //都没有分配空间啊