链栈

//链栈的实现
#include <assert.h>
template <typename VAL_TYPE>
class Stack
{
private:
struct Node
{
VAL_TYPE data;
Node* next;
};
Node* top; //栈顶指针
Node* bottom; //栈底指针
int size;
public:
Stack();
virtual ~Stack();
void push(const VAL_TYPE& val);
void pop();
void get_top(VAL_TYPE& val) const;
void clear();
bool empty() const;
int length() const;
void traverse(int(*visit)(VAL_TYPE&));
};
template <typename VAL_TYPE>
Stack<VAL_TYPE>::Stack()
{
top=bottom=NULL;
size=0;
}
template <typename VAL_TYPE>
Stack<VAL_TYPE>::~Stack()
{
Node* p=NULL;
while(top!=NULL)
{
p=top->next;
delete top;
top=p;
}
bottom=NULL;
size=0;
}
template <typename VAL_TYPE>
void Stack<VAL_TYPE>::clear()
{
~Stack();
}
template <typename VAL_TYPE>
void Stack<VAL_TYPE>::push(const VAL_TYPE& val)
{
Node* new_node=new Node;
new_node->data=val;
new_node->next=top;
top=new_node;
if(bottom==NULL) bottom=top;
size++;
}
template <typename VAL_TYPE>
void Stack<VAL_TYPE>::pop()
{
assert(top!=NULL);
Node* p=top->next;
delete top;
top=p;
size--;
}
template <typename VAL_TYPE>
void Stack<VAL_TYPE>::get_top(VAL_TYPE& val) const
{
assert(top!=NULL);
val=top->data;
}
template <typename VAL_TYPE>
bool Stack<VAL_TYPE>::empty() const
{
return !size;
}
template <typename VAL_TYPE>
int Stack<VAL_TYPE>::length() const
{
return size;
}
template <typename VAL_TYPE>
void Stack<VAL_TYPE>::traverse(int(*visit)(VAL_TYPE& val))
{
Node* p=top;
while(p!=NULL)
{
if(!visit(p->data)) break;
p=p->next;
}
}