顺序存储结构的堆栈

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

#define STACK_MAX_SIZE 20

typedef int elem_t;

typedef struct _stack stack_t;
struct _stack
{
    elem_t data[STACK_MAX_SIZE];
    int top_pt;
};

stack_t *StackCreate(void)
{
    stack_t *s;
    s = (stack_t *)malloc(sizeof(stack_t));
    if (s==NULL)
    {
        printf("could not alloc memory for s");
        exit(1);
    }
    memset(&s->data,0,sizeof(elem_t)*STACK_MAX_SIZE);
    s->top_pt = 0;

    return s;
}

void StackDelete(stack_t *s)
{
    free(s);
}

int StackIsEmpty(stack_t *s)
{
    return !s->top_pt;
}

int StackIsFull(stack_t *s)
{
    return s->top_pt == STACK_MAX_SIZE;
}

void StackPush(stack_t *s,elem_t d)
{
    if(StackIsFull(s))
    {
        printf("stack is full");
        StackDelete(s);
        exit(0);
    }
    
    s->data[s->top_pt] = d;
    s->top_pt++;
}

elem_t StackPop(stack_t *s)
{
    elem_t retval;
    if(StackIsEmpty(s))
    {
        printf("stack is empty");
        StackDelete(s);
        exit(0);
    }
    retval = s->data[s->top_pt-1];
    s->top_pt--;

    return retval;
}

int main(int argc,char *argv[])
{
    stack_t *st;
    int i;
    elem_t retval;

    st = StackCreate();
    
    for (i=0;i<10;i++)
        StackPush(st,'0'+i);
    
    for (i=0;i<11;i++)
    {
        retval = StackPop(st);
        printf("%d,",retval);
    }

    StackDelete(st);

    return 0;
}