问题：字符串的进栈，出栈函数是这样写的吗，但好像还是有点问题？
typedef struct {

  char data[20];
  char top;
} ag_stack;

void ag_init_stack(ag_stack *st)
{
 st->top=0;

}
void ag_state_push(ag_stack *st,char *s)
{
     if(st->top==MAX-1)
         { printf("\nstack is full!"); getch();exit(0); }
  
     strcpy(st->data[st->top],s);
       printf("\naaaaaa");
    st->top++;
}

void ag_state_pop(ag_stack *st)
{

     if(st->top==0)
          { printf("\nstack is empty!"); getch();exit(0);}

     st->top--;

}