描述：
設有兩個棧，S1和S2，都采用順序棧的存儲方式。
兩個棧共享一個存儲區：【0，……maxsize-1】
目的：可以盡量利用空間，減少溢出的可能，采用棧頂相向、迎面增長的存儲方式

PS：要註意判斷棧滿棧空的檢查

#include<stdio.h>
#include<stdlib.h>
#include<iostream>
using namespace std;
#define maxsize 100

/*棧結構的定義*/
typedef struct
{
    int stackk[maxsize];
    int top[2];//兩個棧頂指針top[0]指向stackk左端，top[1]指向stackk右端
 

    int length[2];
} stk;
/*入棧*/
/*i表示兩個不同的棧，0表示左邊的棧，1表示右邊的棧
左邊的棧每入棧一個元素指針向右移動，右邊的棧每入棧一個元素指針向左移動
入棧操作前要判斷棧是否為滿
*/
void initStackk(stk *S)
{
    S->length[0]=0;
    S->length[1]=0;
    S->top[0]=-1;
    S->top[1]=maxsize;
}
int Push(int i,int x,stk *S)
{
    if(i!=0&&i!=1)
    {
        cout
 
<<"wrong stack number"<<endl;
        return 0;
    }
    else if(S->top[0]==(S->top[1]-1))
    {
        cout<<"the stack is filled with data";
        return 0;
    }
    if(i==0)
    {
        S->stackk[++S->top[0]]=x;
        S->length[i]++;
    }
    else
    {
        S
 
->stackk[--S->top[1]]=x;
        S->length[i]++;
    }
    cout<<"Successful."<<endl;
    return 1;
}
int Pop(int i,int &x,stk *S)
{
    if(i!=0&&i!=1)
    {
        cout<<"wrong stack number"<<endl;
        return 0;
    }
    if(S->top[i]==-1||S->top[i]==maxsize)
    {
        cout<<"Stack"<<i<<" is null.";
        return 0;
    }
    if(i==0)
    {
        x=S->stackk[S->top[i]--];
        S->length[i]--;
    }
    else
    {
        x=S->stackk[S->top[i]++];
        S->length[i]--;
    }
    cout<<"Successful."<<endl;
    return 1;
}
void showtheStack(stk *S)
{
    cout<<"Stack0 : ";
    for(int i=0; i<S->length[0]; i++)
        cout<<S->stackk[i]<<" ";
    cout<<endl;
    cout<<"Stack1 : ";
    for(int i=maxsize-1,j=0; j<S->length[1]; j++,i--)
    {
        cout<<S->stackk[i]<<" ";
    }
    cout<<endl;
}
int main()
{
    stk *S=(stk*)malloc(sizeof(stk));
    initStackk(S);
    cout<<"test function ‘Push‘ by input 5 data."<<endl;
    int w=5;
    while(w--)
    {
        cout<<"input a data and which stack that you want to save";
        int a,b;
        cin>>a>>b;

        if(!Push(b,a,S))
        {
            w++;
        }
    }
    showtheStack(S);
    cout<<"test function ‘Pop‘ by input the stack number."<<endl;
    w=3;
    while(w--)
    {
        int out=-1;
        cout<<"input a stack number (0/1):";
        int in;
        cin>>in;
        if(!Pop(in,out,S))
        {
            w++;
        }
        if(out>0)
        {
            cout<<"you Pop the data "<<out<<" successful from stack"<<in<<"."<<endl;
        }
    }
    showtheStack(S);
    return 0;
}

7 線性表-棧-順序存儲的拓展-迎面增長的存儲方式