双端队列 ADT接口 数组实现

Deque ADT接口 DEQUEUE.h:

 #include <stdlib.h>
 #include "Item.h"

 void DEQUEUEinit(int);
 void DEQUEUEerror(void);
 Item DEQUEUEheadget(void);
 Item DEQUEUEtailget(void);
 void DEQUEUEheadput(Item);
 void DEQUEUEtailput(Item);
 int DEQUEUEisEmpty(void);
 int DEQUEUEisFull(void);

Deque ADT接口实现 DEQUEUE.c:

 #include "DEQUEUE.h"

 static Item *q;
 static int N,head,tail;

 void DEQUEUEinit(int maxN)
 {
     q=malloc(maxN*sizeof(Item));
     if(q==NULL)
         DEQUEUEerror();
     head=;
     tail=;
     N=maxN;
 }
 void DEQUEUEerror(void)
 {
     printf("\n空间可能已满或为空");
     exit();
 }
 Item DEQUEUEheadget(void)
 {
     if(DEQUEUEisEmpty())
         DEQUEUEerror();
     Item temp=q[head];
     head=(head+)%N;
     return temp;
 }
 Item DEQUEUEtailget(void)
 {
     if(DEQUEUEisEmpty())
         DEQUEUEerror();
     tail=(tail-+N)%N;
     return q[tail];
 }
 void DEQUEUEheadput(Item ch)
 {
     if(DEQUEUEisFull())
         DEQUEUEerror();
     head=(head-+N)%N;
     q[head]=ch;
 }
 void DEQUEUEtailput(Item ch)
 {
     if(DEQUEUEisFull())
         DEQUEUEerror();
     q[tail]=ch;
     tail=(tail+)%N;
 }
 int DEQUEUEisEmpty(void)
 {
     if(head==tail)
         return ;
     return ;
 }
 int DEQUEUEisFull(void)
 {
     if(((tail+)%N)==head)
         return ;
     return ;
 }

Item.h:

 typedef char Item;

主程序 main.c：

 #include <stdio.h>

 int main(void)
 {
     int N;

     printf("输入需要申请内存大小:");
     if(scanf("%d", &N))
         DEQUEUEinit(N);
     else
         DEQUEUEerror();
     getchar();
     printf("输入%d个字符",N);
     printf("('+'从队头get '*'从队尾get '大写字母'"
               "从队头put '小写字母'从队尾put):\n");

     while((N=getchar())!='\n')
     {
         switch(N)
         {
             case '+':
                 putchar(DEQUEUEheadget());
                 break;
             case '*':
                 putchar(DEQUEUEtailget());
                 break;
             default:
                 if(N>&&N<)
                     DEQUEUEheadput(N);
                 else
                     DEQUEUEtailput(N);
         }
     }

     return ;
 }