两栈共享空间

参考书籍：《大话数据结构》
环境：VS2017

#include<stdio.h>
#include<stdlib.h>

#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0
#define MAXSIZE 20

typedef int Status;
typedef int SElemType;

Status visit(SElemType e)
{
    printf("%d ", e);
    return OK;
}

typedef struct
{
    SElemType data[MAXSIZE];
    int top1;
    int top2;
}SqDoubleStack;

Status InitStack(SqDoubleStack *S)
{
    S->top1 = -1;
    S->top2 = MAXSIZE;
    return OK;
}

Status StackEmpty(SqDoubleStack S)
{
    if (S.top1 == -1 && S.top2 == MAXSIZE)
        return TRUE;
    else
        return FALSE;
}

Status ClearStack(SqDoubleStack *S)
{
    S->top1 = -1;
    S->top2 = MAXSIZE;
    return OK;
}

int StackLength(SqDoubleStack S)
{
    return (S.top1 + 1) + (MAXSIZE - S.top2);
}

Status Push(SqDoubleStack *S, SElemType e, int stackNumber)
{
    if (S->top1 + 1 == S->top2)
        return ERROR;
    if (stackNumber == 1)
        S->data[++S->top1] = e;
    else if (stackNumber == 2)
        S->data[--S->top2] = e;
    return OK;
}

Status Pop(SqDoubleStack *S, SElemType *e, int stackNumber)
{
    if (stackNumber == 1)
    {
        if (S->top1 == -1)
            return ERROR;
        *e = S->data[S->top1--];
    }
    else if (stackNumber == 2)
    {
        if (S->top2 == MAXSIZE)
            return ERROR;
        *e = S->data[S->top2++];
    }
    return OK;
}

Status StackTraverse(SqDoubleStack S)
{
    int i = 0;
    while (i <= S.top1)
    {
        visit(S.data[i++]);
    }
    i = S.top2;
    while (i < MAXSIZE)
    {
        visit(S.data[i++]);
    }
    printf("\n");
    return OK;
}

int main()
{
    int j;
    SqDoubleStack s;
    int e;
    if (InitStack(&s) == OK)
    {
        for (j = 1; j <= 5; j++)
            Push(&s, j, 1);
        for (j = MAXSIZE; j >= MAXSIZE - 2; j--)
            Push(&s, j, 2);
    }

    printf("栈中元素依次为：");
    StackTraverse(s);

    printf("当前栈中元素有：%d \n", StackLength(s));

    Pop(&s, &e, 2);
    printf("弹出的栈顶元素 e=%d\n", e);
    printf("栈空否：%d(1:空 0:否)\n", StackEmpty(s));

    for (j = 6; j <= MAXSIZE - 2; j++)
        Push(&s, j, 1);

    printf("栈中元素依次为：");
    StackTraverse(s);

    printf("栈满否：%d(1:否 0:满)\n", Push(&s, 100, 1));


    ClearStack(&s);
    printf("清空栈后，栈空否：%d(1:空 0:否)\n", StackEmpty(s));

    system("pause");
    return 0;
}