循环数组队列

//   队列的数组实现


#include <cstdio>
#include <cstdlib>
//#define _OJ_

#define maxsize 5
typedef struct Lnode
{
    int front;
    int rear;
    int *elem;
} deque, *Deque;



void
creat_deque(Deque q)
{
    q->elem = (int*) malloc (maxsize * sizeof(int));
    q->front = q->rear = 0;
}

int
isfull(Deque q)
{
    if((q->rear + 1) % maxsize == q->front)
        return 1;
    else
        return 0;
}

int
isempty(Deque q)
{
    if(q->front == q->rear)
        return 1;
    else
        return 0;
}

int
deque_size(Deque q)
{
    return (q->front - q->rear + maxsize) % maxsize;
}

void
endeque(Deque q)
{
    int x;
    scanf("%d", &x);
    q->elem[q->rear] = x;printf("%d\n", q->rear);
    q->rear = (q->rear + 1) % maxsize;
}

int
del_deque(Deque q)
{
    int e;
    e = q->elem[q->front];
    q->front = (q->front + 1) % maxsize;
    return e;
}

int main(int argc, char const *argv[]) {
#ifndef _OJ_  //ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
#endif

    Deque q;
    creat_deque(q);
    printf("isempty == %d\n", isempty(q));
    printf("size == %d\n", deque_size(q));
    printf("full == %d\n", isfull(q));

    int n, i;
    n = 3;
    do
    {
        endeque(q);
    }
    while (!isfull(q)) ;

    while (!isempty(q)) {
      printf("del == %d\n", del_deque(q));
    }
//值得注意的是此数组只可以存入 maxsize -1 个数据


    return 0;
}