数据结构第八篇——链栈

♥注：未经博主同意，不得转载。

链栈

链式存储的栈称为链栈。可用单链表来实现链栈，因此其节点结构与单链表的结构相同。下面给出这种结构的定义：

若要了解顺序栈的内容请跳转至http://www.cnblogs.com/tenjl-exv/p/7575549.html

链栈无栈满问题，空间可扩充，但有栈空问题，栈空的条件为top->next=NULL。插入与删除仅在栈顶处进行，链式栈的栈顶在链表头。

链栈的定义如下：

typedef int Data;
struct StackNode
{
    Data data;
    StackNode *next;
};

class Stack
{
    private:
        StackNode *top;
    public:
        Stack()
        {
            top=new StackNode;
            top->next=NULL;
        }
        ~Stack()
        {
            Clear();
            delete top;
        }
        
        void Push(Data e);
        Data Pop();
        Data GetTop();
        bool IsEmpty();
        void Clear();
        void Print();
};

相关操作算法如下：

//判断栈是否为空 
bool Stack::IsEmpty()
{
    if(top->next==NULL)
    return true;     
    else 
    return false;       
}
//取栈顶元素
Data Stack::GetTop()
{
    if(top->next==NULL)
    {
        cout<<"栈空！"<<endl;
        exit(0); 
    }
    else
    return top->next->data;
} 
//进栈
void Stack::Push(Data x)
{
    StackNode *p;
    p=new StackNode;
    p->data=x;
    p->next=top->next;
    top->next=p;
} 
//出栈
Data Stack::Pop()
{
    StackNode *p=NULL;
    if(top->next==NULL)
    {
        cout<<"栈空"<<endl;
        exit(0);
    }
    else
    {
        p=top->next;
        Data retvalue=p->data;
        top->next=p->next;
        delete p;
        return retvalue;
    }
} 
//清空栈
void Stack::Clear()
{
    StackNode *p;
    while(top->next)
    {
        p=top->next;
        top->next=p->next;
        delete p;
    }
} 
//打印数据
void Stack::Print()
{
    StackNode *p;
    p=top->next;
    while(p)
    {
        cout<<p->data<<"  ";
        p=p->next;
    }
    cout<<endl;
} 

测试部分则放在main函数：

int main()
{
    Stack stack;
    Data a[10]={1,5,8,7,9,5,6,7,4} ;
    Data e;
    if(stack.IsEmpty())
    cout<<"此栈为空"<<endl;
    else
    cout<<"此栈不空"<<endl;
    
    for(int i=0;i<8;++i) 
        stack.Push(a[i]);
        
    stack.Print();
    
    cout<<stack.GetTop()<<endl;
    
    cout<<"进栈：";
    cin>>e;
    stack.Push(e);
    stack.Print();
    cout<<stack.GetTop()<<endl;
    
    cout<<"出栈：";
    stack.Pop();
    stack.Print();
    cout<<stack.GetTop()<<endl;
    
    if(stack.IsEmpty())
    cout<<"此栈为空"<<endl;
    else
    cout<<"此栈不空"<<endl;
    
    cout<<"出栈：";
    stack.Pop();
    stack.Print();
    
    cout<<"清空栈："<<endl;
    stack.Clear();
    
    if(stack.IsEmpty())
    cout<<"此栈为空"<<endl;
    else
    cout<<"此栈不空"<<endl;
     
    return 0;
}

简单的测试结果如下：