用棧設置密碼

#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"; /*密碼，全局變量*/
typedef char SElemType;
typedef struct STACK /*定義棧類型*/
{
SElemType *base;
SElemType *top;
int stacksize;
int length;
}SqStack,*Stack;
typedef int Status;
void InitStack(Stack *S) /*初始化棧*/
{
*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) /* 銷毀棧*/
{
free((*S)->base);
free((*S));
return OK;
}
void ClearStack(Stack *S) /*把棧置為空*/
{
(*S)->top=(*S)->base;
(*S)->length=0;
}
Status StackEmpty(SqStack S) /*判斷棧空否*/
{
if(S.top==S.base) return TRUE;
else
return FALSE;
}
void Push(Stack *S,SElemType e) /*把數據壓入棧*/
{
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) /*刪除棧頂元素*/
{
if((*S)->top==(*S)->base) return ERROR;
(*S)->top--;
--(*S)->length;
return OK;
}
Status GetTop(Stack S,SElemType *e)/*返回棧頂元素*/
{
if(S->top==S->base) return ERROR;
*e=*(S->top-1);
S->top--;
}
void Change(SqStack S,char *a) /*將棧中的元素按反序付給 a */
{ int n=S.length-1 ;
while (!StackEmpty(S))
GetTop(&S,&a[n--]);
}
void Control(Stack *s)
{int i=0,k,j=0;
SElemType ch,*a;
k=strlen(PASSWORD);
printf("輸入一個 %d 個數的密碼,你只有 3 次機會：\n",k);
printf("C:\\>");
for(;;)
{ if(i>=3)
{ i++;
clrscr();
gotoxy(1,1); /*定位黑屏光標位置*/
break;
}
else if(i>0&&i<3)
{ gotoxy(5,2);
for(j=1;j<=(*s)->length;j++)printf(" ");
gotoxy(5,2);ClearStack(s);}
for(;;) /* 密碼輸入，可退格 */
{ch=getch(); /* 退格 的ASCII 是8 */
if(ch!=13) /* 判斷是否為回車，不是則把它付給下面*/
{if(ch==8) {Pop(s);gotoxy(4+j,2);printf(" ");gotoxy(4+j,2);}
else {printf("*");Push(s,ch);}
j=(*s)->length;}
else break;
}
i++;
if(k!=j) continue;
else
{ a=(SElemType *)malloc((*s)->length*sizeof(SElemType));
Change(**s,a);
for(j=1;j<=(*s)->length;)
{if(a[j-1]==PASSWORD[j-1]) j++;
else {j=(*s)->length+2;break;}}
if(j==(*s)->length+2) continue;
else break;}}/*最上面的for完*/
if(i==4) printf("\n密碼錯誤，即將退出");
else printf("\n密碼正確\n");
free(a);
}
main()
{Stack s;
clrscr();/*清屏*/
InitStack(&s);
Control(&s);
getch();
DestroyStack(&s);
}