链式存储的栈的实现

2013-08-18 15:59:58

顺序存储的栈的缺点：

存储空间有限，当栈中元素个数超出定义的栈的MAXSIZE时，再进行插入，就会出现访问越界。当然，可以通过realloc重新分配内存以扩大容量，不过这样不但会增加复杂度，而且要求存储空间是连续的，当内存中没有这么大的连续空间时，就会发生内存溢出；

为了解决这个问题，链式存储的栈不失为好的办法，下面是用链表实现的栈。

用链式存储是实现栈时，注意几点：

1. 将链表头结点作为栈顶，而且也不需要附加的头结点；
2. 栈的结构只有一个链表指针；
3. 栈的初始化，就是将链表头结点置为NULL；
4. 栈的销毁，就是链表的销毁；
5. 栈的push、pop，就是在链表的头部进行插入、删除的操作，在pop时，注意对空栈的处理，下面的代码中用assert(NULL != s.top);检查是否为空；
6. 求栈的长度的操作，就是求链表长度；
7. 获取栈顶元素，就是获取链表头结点元素，注意对空栈的处理，下面的代码中用assert(NULL != s.top);检查是否为空。

---

代码（测试暂未发现错误，欢迎交流指正！）：

#include <iostream>
#include <cassert>
using namespace std;

typedef int DataType; 

typedef struct node
{
    DataType data;
    struct node *next;
}LNode,*PLNode;

typedef struct stack
{
    PLNode top;
}Stack;

//初始化栈
void InitStack(Stack &s)
{
    s.top = NULL;  //不需头结点
}

//初始化栈
void DestoryStack(Stack &s)
{
    PLNode pPre = s.top;
    PLNode pCur = pPre->next;
    while (NULL != pCur)
    {
        delete pPre;
        pPre = pCur;
        pCur = pCur->next;
    }
}

//出栈
void PushStack(Stack &s,DataType data)
{
    PLNode pNew = new LNode;
    pNew->data = data;

    pNew->next = s.top;
    s.top = pNew;
}

//出栈
DataType PopStack(Stack &s)
{
    assert(NULL != s.top);

    DataType topData = s.top->data;

    PLNode headToDelete = s.top;
    s.top = s.top->next;
    delete headToDelete;

    return topData;
}

//获取栈顶元素
DataType GetTopOfStack(Stack &s)
{
    assert(NULL != s.top);
    return ( s.top->data );
}

//获取栈中元素个数
size_t GetLengthOfStack(Stack &s)
{
    size_t lengthOfStack = 0;
    PLNode pCur = s.top;
    while (NULL != pCur)
    {
        ++lengthOfStack;
        pCur = pCur->next;
    }

    return lengthOfStack;
}

void DisplayStack(Stack &s)
{
    PLNode pCur = s.top;
    while (NULL != pCur)
    {
        cout<<pCur->data<<"	";
        pCur = pCur->next;
    }
    cout<<endl;
}

//栈测试
void TestStack()
{
    Stack s;
    InitStack(s);
    size_t command = 0;

    const size_t PUSH = 0;
    const size_t POP = 1;
    const size_t GETLENGTH = 2;
    const size_t GETTOP = 3;

    DataType data;

    cout<<"Please enter the command ,end with ctrl+z : "<<endl;
    while (cin>>command)
    {
        switch(command)
        {
        case(PUSH):
            {
                cout<<"Please enter z data to push : "<<endl;
                cin>>data;
                cout<<"push "<<data<<endl;

                cout<<"the stack before push : "<<endl;
                DisplayStack(s);

                PushStack(s,data);    

                cout<<"the stack after push : "<<endl;
                DisplayStack(s);

                break;
            }

        case(POP):
            {
                cout<<"the stack before pop : "<<endl;
                DisplayStack(s);

                cout<<"pop "<<PopStack(s)<<endl;    

                cout<<"the stack after pop : "<<endl;
                DisplayStack(s);

                break;
            }

        case(GETLENGTH):
            {
                cout<<"the length of stack is : "<<GetLengthOfStack(s)<<endl;

                break;
            }

        case(GETTOP):
            {
                cout<<"the top element of stack is : "<<GetTopOfStack(s)<<endl;

                break;
            }
        default:
            break;
        }
        cout<<"Please enter the command ,end with ctrl+z : "<<endl;
    }

    DestoryStack(s); //销毁栈
}

int main()
{
    TestStack();
    return 0;
}

测试结果：

Please enter the command ,end with ctrl+z :
2
the length of stack is : 0
Please enter the command ,end with ctrl+z :
0
Please enter z data to push :
1
push 1
the stack before push :

the stack after push :
1
Please enter the command ,end with ctrl+z :
0
Please enter z data to push :
2
push 2
the stack before push :
1
the stack after push :
2       1
Please enter the command ,end with ctrl+z :
0
Please enter z data to push :
3
push 3
the stack before push :
2       1
the stack after push :
3       2       1
Please enter the command ,end with ctrl+z :
0
Please enter z data to push :
4
push 4
the stack before push :
3       2       1
the stack after push :
4       3       2       1
Please enter the command ,end with ctrl+z :
1
the stack before pop :
4       3       2       1
pop 4
the stack after pop :
3       2       1
Please enter the command ,end with ctrl+z :
1
the stack before pop :
3       2       1
pop 3
the stack after pop :
2       1
Please enter the command ,end with ctrl+z :
1
the stack before pop :
2       1
pop 2
the stack after pop :
1
Please enter the command ,end with ctrl+z :
2
the length of stack is : 1
Please enter the command ,end with ctrl+z :
2
the length of stack is : 1
Please enter the command ,end with ctrl+z :
1
the stack before pop :
1
pop 1
the stack after pop :

Please enter the command ,end with ctrl+z :
1
the stack before pop :

Assertion failed: NULL != s.top, file e:visual studio 2010_projectslink_stack_
2013_08_17link_stack_2013_08_17link_stack.cpp, line 50
请按任意键继续. . .