C语言—栈

栈的操作：进栈和出栈

#include "stdafx.h"
#include "stack.h"
#define maxsize  20
typedef int Elemtype;

/*顺序存储—数组形式*/
struct stack
{
    int data[maxsize];
    int top;
};

void init(struct stack *ps)
{
    ps->top = -1;
}

void init2(struct Doublestack * ps)
{
    ps->top1 = -1;
    ps->top2 =maxsize;
}

void  print(int a[],int len)
{
    int i;
    // len = sizeof(a) / sizeof(a[0]);这样子你得不到长度的，此时a退化为了指针
    for (i = 0; i <= len - 1; i++)
    {
        printf("%d\n", a[i]);
    }
}
int push(struct stack * s, int e)
{
    if (s->top == maxsize - 1)
        return -1;    
    s->data[++s->top] = e;    
    return 0;
}

Elemtype  pop(struct stack *s)
{
    int n;
    if (s->top == 0)
        return -1;
    n = s->data[s->top--];
    
    return n;
}

//两栈共享
struct Doublestack
{
    int data[maxsize];
    int top1;
    int top2;
};

int push_two(struct Doublestack *s, int e, int stackflag)
{
    if (s->top1 == s->top2 - 1)  //full stack
        return -1;
    if (stackflag == 1)
    {
        s->data[++s->top1] = e;
    }
    else if (stackflag == 2)
    {
        s->data[--s->top2] = e;
    }
    return 0;
}
Elemtype pop_two(struct Doublestack *s,  int stackflag)
{
    int n;
    if (stackflag == 1)
    {
        if (s->top1 == -1)  //s1 empty
            return -1;
        n = s->data[s->top1--];
    }
    else if (stackflag == 2)
    {
        if (s->top2 ==maxsize)  //s2 empty
            return -1;
        n = s->data[s->top2++];
    }
    //printf("%d\n", n);
    return n;
}

主函数

#include "stdafx.h"
#include  "link.h"
#include "stack.h"

int main()
{
    
    /*stack_test*/
    //struct stack s;
    //struct stack *ps = &s;
    //init(ps);

    struct Doublestack s;
    struct Doublestack * ps = &s;
    init2(ps);
    int e = 1;
    int n;
    //push( ps,  e);
    //push(ps, 2);
    //print(ps->data,2);
    //n = pop(ps);
    //printf("%d\n", n);

    push_two(ps, e,1);
    push_two(ps, 2, 2);
    print(ps->data, 20);
     n=pop_two(ps,1);
    printf("n =%d\n", n);

    system("pause");


}