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=0;
    tail=0;
    N=maxN;
}
void DEQUEUEerror(void)
{
    printf("\n空间可能已满或为空");
    exit(1);
}
Item DEQUEUEheadget(void)
{
    if(DEQUEUEisEmpty())
        DEQUEUEerror();
    Item temp=q[head];
    head=(head+1)%N;
    return temp;
}
Item DEQUEUEtailget(void)
{
    if(DEQUEUEisEmpty())
        DEQUEUEerror();
    tail=(tail-1+N)%N;
    return q[tail];
}
void DEQUEUEheadput(Item ch)
{
    if(DEQUEUEisFull())
        DEQUEUEerror();
    head=(head-1+N)%N;
    q[head]=ch;
}
void DEQUEUEtailput(Item ch)
{
    if(DEQUEUEisFull())
        DEQUEUEerror();
    q[tail]=ch;
    tail=(tail+1)%N;
}
int DEQUEUEisEmpty(void)
{
    if(head==tail)
        return 1;
    return 0;
}
int DEQUEUEisFull(void)
{
    if(((tail+1)%N)==head)
        return 1;
    return 0;
}

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>64&&N<91)
                    DEQUEUEheadput(N);
                else
                    DEQUEUEtailput(N);
        }
    }
    
    return 0;
}