动态栈

动态栈

1. 栈:动态栈和静态栈
   ->动态栈的基本内核是单链表(离散存储)(砍掉单链表的一些操作[对单链表增加一些限制条件]就可以形成栈);
   ->静态栈的基本内核是一维数组(连续存储)。

2. 栈的特点:数据元素遵从’先进后出’的规则

/*    ********************动态栈*******************/# include <stdio.h># include <malloc.h>//包含malloc()函数的声明# include <stdlib.h>//包含exit()函数的声明//自定义节点结构体typedef struct Node{    int data;    struct Node * pNext;}NODE, * PNODE; //自定义栈结构体typedef struct Stack{    PNODE pTop;    PNODE pBottom;}STACK, * PSTACK;//declare functionvoid InitStack(PSTACK pS);void PushStack(PSTACK pS,int val);void TraverseStack(PSTACK pS);int  GetTop(PSTACK pS);PNODE PopStack(PSTACK pS);bool EmptyStack(PSTACK pS);void GetDelTop(PSTACK pS,int * pVal);int GetLength(PSTACK pS);int main(void){    STACK S;//建立栈S    int val;//初始化栈    InitStack(&S);//压栈    PushStack(&S,1);    PushStack(&S,2);    PushStack(&S,3);    PushStack(&S,4);    printf("Output(traverse):");    TraverseStack(&S);//遍历栈[遍历相当于指全部浏览一遍并不进行任何操作]    printf("stack length: %d\n\n",GetLength(&S));//读栈顶元素    val = GetTop(&S);    printf("pTop value: %d\n",val);//读取并删除栈顶元素    printf("get and delete pTop:\n");    GetDelTop(&S,&val);    printf("pTop value: %d\n",val);    printf("stack length: %d\n\n",GetLength(&S));//出栈    printf("popstack:\n");    PopStack(&S);    printf("stack length: %d\n\n",GetLength(&S));    return 0;}//initialize stackvoid InitStack(PSTACK pS){    pS->pTop = (PNODE)malloc(sizeof(NODE));//建立一个新节点（作用:让pTop和pBottom同时指向这个节点）    if(NULL == pS->pTop)    {        printf("ALLOCATION IS FAILED!\n");        exit(-1);//内存分配不成功直接退出程序    }    else    {        pS->pBottom = pS->pTop;        pS->pBottom->pNext = NULL;//初始化pBottom指针指向的节点的指针域为空(类似于单链表的头结点(它没任何作用只是便于链表操作))    }    return;}//push stackvoid PushStack(PSTACK pS,int val){    PNODE pNew = (PNODE)malloc(sizeof(NODE));    pNew->data = val;    pNew->pNext = pS->pTop;//链接新节点和栈顶指针    pS->pTop = pNew;//栈顶指针指向新节点    return;}//traverse stackvoid TraverseStack(PSTACK pS){    PNODE p = pS->pTop;//必须新建一个指针p(指向栈顶指针指向的存储单元)，不能直接操作栈顶指针因为会改变栈(遍历操作是不会改动栈的)    while(p != pS->pBottom)    {        printf("%-3d",p->data);        p = p->pNext;       }    printf("\n");    return;}//determine whether stack is empty or notbool EmptyStack(PSTACK pS){    if(pS->pTop == pS->pBottom)//起初建立并初始化栈的时候满足其中一个条件'pS->pTop == pS->pBottom'    {        return true;    }    else    {        return false;    }}//get the value of pTopint  GetTop(PSTACK pS)//因为要读栈顶元素的值所以应该返回一个数据类型是'int'的值{    if(EmptyStack(pS))    {        printf("STACK IS EMPTY!\n");        return 0;    }    else    {        return pS->pTop->data;    }}//pop stackPNODE PopStack(PSTACK pS)//出栈指的是移出整个节点所以声明的数据类型是'PNODE'{    if(EmptyStack(pS))    {        printf("STACK IS EMPTY!\n");        return NULL;    }    else    {        PNODE p = pS->pTop;        pS->pTop = pS->pTop->pNext;        free(p);//释放指针p指向的存储单元里的数据        p = NULL;//清空变量名为p的存储单元        return pS->pTop;    }}//get and delete pTopvoid GetDelTop(PSTACK pS,int * pVal)//将获取的值存入指针pVal指向的存储单元中{    if(EmptyStack(pS))    {        printf("STACK IS EMPTY!\n");    }    else    {        * pVal = GetTop(pS);        PopStack(pS);    }    return;}//get the length of stackint GetLength(PSTACK pS){    int cnt = 0;//代表栈的有效长度    PNODE p = pS->pTop;//必须加一个指向‘pS->pTop’的指针p否则‘pS->pTop’会随着操作改变从而整个‘栈’会改变    if(EmptyStack(pS))    {        printf("STACK IS EMPTY!\n");        return 0;    }    else    {        while(p != pS->pBottom)        {            ++cnt;            p = p->pNext;//指针指向下一个节点        }        return cnt;    }}