栈 --C

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

#define TRUE 1
#define FALSE 0

typedef struct node {
  int data;
  struct node *next;
} Stack;


/*栈初使化*/
void StackInit(Stack *top)
{
    top->next = NULL;
}


/*进栈*/
int Push(Stack *top, int x)
{
    Stack *p;
    p = (Stack *)malloc(sizeof(Stack));
    if(p == NULL)
        return FALSE;
    p->data = x;
    p->next = top->next;
    top->next = p;
    return TRUE;
}


/*栈顶指针是否为空*/
int IsEmpty(Stack *top)
{
    if(top->next == NULL)
        return TRUE;
    return FALSE;
}

/*出栈*/
int Pop(Stack *top, int *x)
{
    Stack *p;
    if(IsEmpty(top))
        return FALSE;
    p = top->next;
    *x = p->data;
    top->next = p->next;
    free(p);
    return TRUE;
}

int main()
{
  int x;
  Stack *top = (Stack *)malloc(sizeof(Stack));
  StackInit(top);                        /* 栈初始化 */
  printf("input some positive integers:\n");
  scanf("%d", &x);
  while(x > 0)
  {
    Push(top, x);                        /* 进栈 */
    scanf("%d", &x);
  }
  while(Pop(top, &x))                    /* 出栈 */
  {
    printf("%d ", x);                         /* 输出到屏幕 */
  }
  printf("\n", x);
  return 0;
}