#include<stdio.h>
#include<stdlib.h>#define ok 1
#define error 0
#define maxsize 90//最大队列长度typedef int status;
typedef int qelemtype;typedef struct{qelemtype *base;int front;int rear;
}sqqueue;status initqueue(sqqueue &q)//构造一个空队列
{q.base = (qelemtype*)malloc(maxsize*sizeof(qelemtype));if (!q.base)return error;q.front = q.rear = 0;return ok;
}void queuelength(sqqueue q)//求队列的长度
{int len = (q.rear - q.front) % maxsize;printf("此时循环队列的长度为:%d\n", len);
}status enqueue(sqqueue &q, qelemtype e)//插入元素e为q的新的队尾元素
{if ((q.rear + 1) % maxsize == q.front)return error;//队列满q.base[q.rear] = e;q.rear = (q.rear + 1) % maxsize;//队尾+1，但此时的q.rear还是随机值return ok;
}status dequeue(sqqueue &q, qelemtype &e)//删除队头元素
{if (q.front == q.rear)return error;e = q.base[q.front];q.front = (q.front + 1) % maxsize;return ok;
}status queuetraverse(sqqueue q)//输出队列中的元素
{printf("此时的队列状态为:");while (q.front <q.rear)//队列中的元素从q.front~q.rear-1;{printf("%4d", q.base[q.front]);q.front++;}printf("\n");return ok;
}status gethead(sqqueue q, qelemtype &e)//取队头元素
{if (q.front == q.rear)return error;e = q.base[q.front];return ok;
}status clearqueue(sqqueue &q)//清空队列
{q.front = q.rear;return ok;
}status destoryqueue(sqqueue &q)//销毁队列
{free(q.base);return ok;
}status queueempty(sqqueue q)//队列判空
{if (q.front == q.rear)return ok;elsereturn error;
}int main()
{sqqueue q;qelemtype e;int i;if (initqueue(q) == ok)printf("队列创建成功!\n");elseprintf("队列创建失败！\n");for (i = 1; i <= 5; i++)enqueue(q, i*2);queuetraverse(q);queuelength(q);printf("将20插入到队列中\n");enqueue(q, 20);queuetraverse(q);queuelength(q);printf("队头元素出队列\n");dequeue(q, e);queuetraverse(q);printf("出队列的元素是:%d\n", e);gethead(q, e);printf("新的队头元素为:%d\n", e);if (queueempty(q) == ok)printf("队列为空!\n");elseprintf("队列不为空！\n");if (clearqueue(q) == ok)printf("置空成功!\n");destoryqueue(q);system("pause");return ok;}