C语言-数据结构-共享栈

/*

共享栈

2018/8/4

利用栈底位置不对称性,可以让两个顺序栈共享一个一维数据空间,
将两个栈的栈底分别设置为共享空间的两端,两个栈顶向共享空间中间延伸,
两个栈的栈顶指针都指向了两个栈顶元素,
top1=-1时,栈1为空,top2=MAX_SIZE,栈2为空
栈顶指针相邻时(–top2 = top1)栈满,

共享栈为了更加有效的利用存储空间,同时只有整个存储空间被占满,发生上溢
*/

#include "stdio.h"
#include "stdlib.h"
#include "stdbool.h"
#include "malloc.h"'


#define MAX_SIZE 10
#define stack1 1
#define stack2 2

#define stack1Empty 2
#define stack2Empty 3

typedef struct SharedStack{
    int *PBase;
    int top1;
    int top2;
}Stack,*PStack; 


PStack CreateShareStack(void);  //创建栈 
bool  ShareStackFull(PStack);  //判满返1
int  ShareStackEmpty( PStack S); //判空返1 2 3 0
int ShareStackPush(PStack S, int which, int val); //PUSH
int ShareStackPop(PStack S, int which, int *val); //pop 
int ShareStackDisplay(PStack S);  //printing 


int main()
{
    int val,i;
    int a[10]={1,2,3,4,5,6,7,8,9,10};
    PStack S = CreateShareStack();

    for(i=0; i<5; i++)
    {
        ShareStackPush(S,stack1,i); 
    }

    for(i=10; i>5; i--)
    {
        ShareStackPush(S,stack2,i); 
    }
    ShareStackDisplay(S); 
    ShareStackPush(S,stack1,33);
    ShareStackDisplay(S);
    ShareStackPush(S,stack2,44);        
    ShareStackDisplay(S);

    for(i=0; i<5; i++)//pop出三个 
    {       
        ShareStackPop(S,stack1,&val); 
    }   
    ShareStackDisplay(S);
    ShareStackPop(S,stack1,&val); 
    ShareStackDisplay(S);


    printf("\nHello world!\n");
    return;
} 



/* 创建共享栈 */
PStack CreateShareStack(void)
{
    PStack S = (PStack)malloc(sizeof(Stack));
    S->top1 = -1;
    S->top2 = MAX_SIZE;
    S->PBase = (int*)malloc(sizeof(int) * MAX_SIZE);
    printf("Success create stack!\n");
    return S;
} 

/* 判为满 返1 */
bool  ShareStackFull(PStack S)
{
    return ((S->top2 - 1) == S->top1 ) ? true:false;
}

/* 判为空 全空返1 全不空返0 栈1空返2 栈2空返3 */
int  ShareStackEmpty( PStack S)
{
    if( (S->top1 == -1) && (S->top2 == MAX_SIZE) ) 
    {
        printf("两栈全空\n");return 1; 
    }   
    if(S->top1 == -1 && S->top2 != MAX_SIZE ) return stack1Empty; //栈1空     
    if(S->top1 != -1 && S->top2 == MAX_SIZE ) return stack2Empty; //栈2空
    else return 0;  
} 

/* val  Push 到 第which 栈 */ 
int ShareStackPush(PStack S, int which, int val)
{
    if(ShareStackFull(S))
    {
        printf("栈空间已满,请释放空间后在压栈!\n");return;
    }   
    if(which == stack1)
    {
        S->PBase[++S->top1] = val;
    }else 
    {
        S->PBase[--S->top2] = val;
    }
    return; 
}

/* Pop 第which 栈 到val  */ 
int ShareStackPop(PStack S, int which, int *val)
{
    int i = ShareStackEmpty(S);  //1全空 0全不空 2 1空 3 2空 
    if(i == 1) return;

    if(which == stack1) 
    if(i == 0 || i == 3)
    {       
        *val = S->PBase[S->top1--] ;
    } else if(i == 2)
    {
        printf("栈1已空\n");return;
    } 

    if(which == stack2)
    if(i == 0 || i == 2)
    {       
        *val = S->PBase[S->top2++];
    } else if(i == 3)
    {
        printf("栈2已空\n");return;
    }    
    return; 
}

/* 打印两个栈  */ 
int ShareStackDisplay(PStack S)
{
    if(ShareStackEmpty(S) == 1)return;//两栈全空时取消打印       
    printf("栈1的有效数据: ");
    int i;
    for(i=0; i <= S->top1; i++)
    {
        printf("%d ",S->PBase[i]);
    }

    printf("  栈2的有效数据: ");
    i = MAX_SIZE - 1;

    for(i=MAX_SIZE-1; i >= S->top2; i--)
    {
        printf("%d ",S->PBase[i]);
    }
    printf("\n");       
}