用栈设置密码

#include<stdio.h>
#include<string.h>
#include<conio.h>
#include<stdlib.h>
#define STACK_INIT_SIZE 10
#define OK 1
#define TRUE 1
#define FALSE  0
#define ERROR 0
char PASSWORD[10]="abcdef"; /*密码，全局变量*/
typedef char SElemType;
typedef struct STACK /*定义栈类型*/
{
  SElemType *base;
  SElemType *top;
  int stacksize;
  int length;
}SqStack,*Stack;
typedef int Status;
void InitStack(Stack *S) /*初始化栈*/
{
  *S=(SqStack *)malloc(sizeof(SqStack));
  (*S)->base=(SElemType *)malloc(STACK_INIT_SIZE*sizeof(SElemType));
  if(!(*S)->base)exit(-1);
  (*S)->top=(*S)->base;
  (*S)->stacksize=STACK_INIT_SIZE;
  (*S)->length=0;
}
Status DestroyStack(Stack *S) /* 销毁栈*/
{
 free((*S)->base);
 free((*S));
 return OK;
}
void ClearStack(Stack *S)  /*把栈置为空*/
{
  (*S)->top=(*S)->base;
  (*S)->length=0;
}
Status StackEmpty(SqStack S) /*判断栈空否*/
{
  if(S.top==S.base) return TRUE;
  else
    return FALSE;
}
void Push(Stack *S,SElemType e)  /*把数据压入栈*/
{
  if((*S)->top - (*S)->base>=(*S)->stacksize)
   {
     (*S)->base=(SElemType *) realloc((*S)->base,
     ((*S)->stacksize + 2) * sizeof(SElemType));
     if(!(*S)->base)exit(-1);
     (*S)->top=(*S)->base+(*S)->stacksize;
     (*S)->stacksize += 2;
   }
  *((*S)->top++)=e;
  ++(*S)->length;
}
Status Pop(Stack *S) /*删除栈顶元素*/
{
  if((*S)->top==(*S)->base) return ERROR;
  (*S)->top--;
  --(*S)->length;
  return OK;
}
Status GetTop(Stack S,SElemType *e)/*返回栈顶元素*/
{
  if(S->top==S->base) return ERROR;
  *e=*(S->top-1);
  S->top--;
}
void Change(SqStack S,char *a) /*将栈中的元素按反序付给 a */
{ int n=S.length-1 ;
  while (!StackEmpty(S))
      GetTop(&S,&a[n--]);
}