栈_0311

//stack.c

//用结构体数组实现栈

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

#define NUM 10

typedef struct stack
{
    int top;
    char stack[NUM];
}stack_t;

void init(stack_t *st)
{
    memset(st, 0, sizeof(stack_t));
}

void push(stack_t *st, char n)
{
    st->stack[st->top++] = n;
}

char pop(stack_t *st)
{
    return st->stack[-- st->top];
}

bool is_empty(stack_t *st)
{
    return st->top == 0;
}

bool is_full(stack_t *st)
{
   return st->top == NUM ;
}

int main(int argc, const char *argv[])
{
    char ch;
    stack_t st;

    init(&st);

    while(! is_full(&st))
    {
        ch = getchar();

        if(ch == '\n')
            break;
        push(&st, ch);
    }

    while(! is_empty(&st))
        putchar(pop(&st));
    putchar('\n');

    return 0;
}

//stack_link.c

//用链表实现栈

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

#define MAX 128

typedef struct node
{
    void *data;
    struct node *next;
}node_t;


typedef struct
{
    node_t *top;
}top_t;

void init_top(top_t *t)
{
   t->top = NULL;
}

void push(top_t *st, void *data)
{
    node_t *cur;

    cur = malloc(sizeof(node_t));
    if(cur == NULL)
    {
        printf("malloc fail\n");
        exit(1);
    }

    cur->data = data;
    cur->next = NULL;

    if(st->top == NULL)
        st->top = cur;
    else
    {
       cur->next = st->top;
       st->top = cur;
    }
}

node_t *pop(top_t *st)
{
    node_t *cur;

    cur = st->top;
    st->top = cur->next;

    return cur;
}

bool is_empty(top_t *st)
{
    return st->top == NULL;
}



int main(int argc, const char *argv[])
{
    char ch;
    char *p;
    top_t st;

    init_top(&st);

    while((ch = getchar()) != '\n')
    {
        p = malloc(sizeof(char));
        *p = ch;
        push(&st, p);
        //push(&st, &ch);
        //此处压的是一个char类型的地址，push完成将该地址内的值压栈，ch最后存的是'\n'
    }
    while(! is_empty(&st))
    {
        node_t *cur = pop(&st);
        printf("-%c-", *((char *)(cur->data)));
        free(cur);
    }

    free(p);
    putchar('\n');
    return 0;
}