数据结构-栈

栈的简介

栈是一种特殊的线性表，仅能在线性表的一端操作，栈顶允许操作，栈底不允许操作。

具有后进先出（Last In First Out）特性

栈的基本操作具有：初始化栈，入栈，出栈，判断栈是否空，获取栈顶数据，获取栈的元素个数，清空栈，销毁栈

 

顺序结构实现栈：

栈的结构体设计：

typedef struct

{

ElemType *elem;    //数组或者指针，用于存放栈数据，指针的话需要分配空间

int top;    //栈顶位置，用于记录当前栈顶在哪

int size;    //栈的大小

}STACK_SQ;

 

接口实现：

//初始化栈，给栈分配空间，初始值，成功返回true，出错返回false

bool InitStack(STACK_SQ &sq, int size);

 

//入栈，需要判断是否已达栈顶，如果达到栈顶，退出。成功返回true，出错返回false

bool PushStack(STACK_SQ &sq, ElemType e);

 

//出栈，需要判断是否为空栈，是则退出，出栈成功返回出栈元素，出错返回-1

int PopStack(STACK_SQ &sq， ElemType &e);

 

//判断栈是否为空，如果为空，返回true，出错返回false；

bool IsEmptyStack(STACK_SQ sq);

 

//获取栈顶数据，需要判断是否是空栈，获取成功返回true，失败返回false

bool GetTopStack(STACK_SQ sq, ElemType &e);

 

//获取栈的元素个数，空的话返回0，返回元素个数

int GetNumStack(STACK_SQ sq);

 

//清空栈

void ClearStack(STACK_SQ &sq);

 

//销毁栈

void DestroyStack(STACK_SQ &sq);

 

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <string.h>
using std::cout;
using std::endl;
typedef int ElemType;

//栈结构体
typedef struct
{
    ElemType *elem;
    int top;
    int size;
}STACK_SQ;
//初始化栈
bool InitStack(STACK_SQ &sq, int size)
{
    sq.elem = (ElemType *)malloc(size * sizeof(ElemType));
    if(sq.elem == NULL)    return false;
    sq.top = 0;
    sq.size = size;
    return true;
}
//入栈
bool PushStack(STACK_SQ &sq, ElemType e)
{
    //判断是否已到栈顶
    if(sq.top >= sq.size )
    {
        cout<<"out of stack size"<<endl;
        return false;
    }
    sq.elem[sq.top++] = e;
    //sq.elem+(sq.top++) = e;
    return true;
}
//出栈
int PopStack(STACK_SQ &sq, ElemType &e)
{
    if(sq.top == 0)
    {
        cout<<"stack is empty!"<<endl;
        return -1;
    }
    e = sq.elem[sq.top - 1];
    sq.top--;
    return e; 
}
//判断栈是否为空
bool IsEmptyStack(STACK_SQ sq)
{
    if(0 == sq.top)
        return true;
    return false;
}
//获取栈顶元素
bool GetTopStack(STACK_SQ sq, ElemType &e)
{
    if(0 == sq.top)
    {
        cout<<"stack is empty!"<<endl;
        return false;
    } 
    e = sq.elem[sq.top - 1];
    return true;
}
//获取栈的元素个数
int GetNumStack(STACK_SQ sq)
{
    int size = sq.top;
    return size;
}
//清空栈
void ClearStack(STACK_SQ &sq)
{
    sq.top = 0; 
    //sq.size = 0;
}
//销毁栈
void DestoryStack(STACK_SQ &sq)
{
    sq.top = 0;
    sq.size = 0;
    free(sq.elem);
    sq.elem = NULL;
}
const int SIZE = 10;
int main()
{
    cout<<"init stack"<<endl;
    STACK_SQ sq;    
    if(!InitStack(sq, SIZE))
    {
        cout<<"init stack fail!"<<endl;
        return -1;
    }
    cout<<"init stack success!"<<endl;
    int a[SIZE] = {1,2,3,4,5,6,7,8,9,10};
    for(int i = 0; i < SIZE; i++)
    {
        if(!PushStack(sq, a[i]))
        {
            cout<<a[i]<<":push stack faile!"<<endl;
            break;
        }
        cout<<"push stack:"<<a[i]<<endl;
    }
    cout<<"push stack success!"<<endl;
    cout<<"num stack:"<<GetNumStack(sq)<<endl;
    ElemType e; 
    for(int i = 0; i < SIZE; i++)
    {
        if(PopStack(sq, e) != -1)
        {
            cout<<"pop stack:"<<e<<endl;
        }
    }
    cout<<"clear stack"<<endl;
    ClearStack(sq);
    cout<<sq.size<<endl;
    cout<<"destory stack"<<endl;
    DestoryStack(sq);
    cout<<sq.size<<endl;
    return 0;
}

打印结果：

init stack
init stack success!
push stack:1
push stack:2
push stack:3
push stack:4
push stack:5
push stack:6
push stack:7
push stack:8
push stack:9
push stack:10
push stack success!
total num stack:10
pop stack:10
pop stack:9
pop stack:8
pop stack:7
pop stack:6
pop stack:5
pop stack:4
pop stack:3
pop stack:2
pop stack:1
clear stack
10
destory stack
0

参考：

https://github.com/huihut/interview/edit/master/DataStructure/SqStack.cpp#L1

 

https://blog.51cto.com/9291927/2063393