1 #include<iostream>
2 #include<stdlib.h>
3 using namespace std;
4
5 typedef int QElemType;
6 typedef int Status;
7 #define MAXSIZE 10
8 #define OVERFLOW -2
9 #define OK 1
10 #define ERROR 0
11
12 //循环队列的存储结构
13 typedef struct
14 {
15 QElemType *base; //存储空间的基地址
16 int front; //头指针
17 int rear; //尾指针
18 }SqQueue;
19
20 //循环队列的初始化
21 Status InitQueue(SqQueue &Q)
22 {
23 Q.base = new QElemType[MAXSIZE]; //为队列分配一个最大容量为MAXSIZE的数组空间
24
25 if (!Q.base) //分配失败
26 exit(OVERFLOW);
27
28 Q.front = Q.rear = 0; //头指针和尾指针置为0，对列为空
29
30 return OK;
31 }
32
33 //队列长度
34 int QueueLength(SqQueue Q)
35 {
36 return (Q.rear - Q.front + MAXSIZE) % MAXSIZE; //循环队列，取余
37 }
38
39 //入队
40 //插入元素e，作为队列Q的新的队尾元素
41 Status EnQueue(SqQueue &Q, QElemType e)
42 {
43 if ((Q.rear + 1) % MAXSIZE == Q.front) //尾指针在循环意义上加1后等于头指针，表明对满
44 return ERROR;
45
46 Q.base[Q.rear] = e; //新元素插入队尾
47
48 Q.rear = (Q.rear + 1) % MAXSIZE; //队尾指针加1
49
50 return OK;
51 }
52
53 //出队
54 //删除Q的队头元素，用e返回其值
55 Status DeQueue(SqQueue &Q, QElemType &e)
56 {
57 if (Q.front == Q.rear) //队空
58 return ERROR;
59
60 e = Q.base[Q.front]; //保存队头元素
61
62 Q.front = (Q.front + 1) % MAXSIZE; //出队，队头指针加1
63
64 return OK;
65 }
66
67 //取队头元素
68 //返回队头元素，不修改头指针
69 QElemType GetHead(SqQueue Q)
70 {
71 if (Q.front != Q.rear) //队列非空
72 return Q.base[Q.front];
73 }
74
75 int main()
76 {
77 int i, e;
78 int len;
79 SqQueue Q;
80
81 InitQueue(Q); //初始化一个空队列
82
83 for (i = 0; i < MAXSIZE; i++)
84 EnQueue(Q, i); //入队
85
86 len = QueueLength(Q);
87
88 cout << "当前队列情况为：";
89
90 for (i = Q.front; i < Q.rear; i++)
91 {
92 cout << Q.base[i] << " ";
93 }
94 cout << endl;
95
96 cout << "当前队列里的元素有" << len << "个" << endl;
97
98 cout << "当前的队头元素是：" << GetHead(Q) << endl;
99
100 cout << "出队元素有：";
101 for (i = 0; i < 3; i++)
102 {
103 DeQueue(Q, e); //出队
104 cout << e << " ";
105 }
106 cout << endl;
107
108 len = QueueLength(Q);
109
110 cout << "当前队列情况为：";
111
112 for (i = Q.front; i < Q.rear; i++)
113 {
114 cout << Q.base[i] << " ";
115 }
116 cout << endl;
117
118 cout << "当前队列里的元素有" << len << "个" << endl;
119
120 cout << "当前的队头元素是：" << GetHead(Q) << endl;
121
122 system("pause");
123 return 0;
124 }
