队列的实现

  1 #include <cstdio>
  2 #include <cstdlib>
  3 #include <iostream>
  4 using namespace std;
  5 typedef int datatype;
  6 const int maxsize = 100;
  7 struct seqQueue
  8 {
  9     datatype queue[maxsize];
 10     int front;    //指向队头的前一个数据，若和rear相等则说明队空
 11     int rear;    //队尾，下标
 12 };
 13 
 14 //初始化队
 15 void init(seqQueue &q)
 16 {
 17     q.front = q.rear = maxsize - 1;
 18 }
 19 
 20 //入队
 21 void enQueue(seqQueue &q, datatype e)
 22 {
 23     if ((q.rear + 1) % maxsize == q.front)
 24         cout << "溢出" << endl;
 25     else
 26     {
 27         q.rear = (q.rear + 1) % maxsize;
 28         q.queue[q.rear] = e;
 29     }
 30 }
 31 
 32 //出队
 33 datatype delQueue(seqQueue &q)
 34 {
 35     if (q.rear == q.front)
 36     {
 37         cout << "下溢出" << endl;
 38         return 0;
 39     }
 40     else
 41     {
 42         q.front = (q.front + 1) % maxsize;
 43         return q.queue[q.front];    //front是队头的前一个数据的下标
 44     }
 45 }
 46 
 47 //判断是否队空
 48 bool isEmpty(seqQueue &q)
 49 {
 50     return q.rear == q.front ? true : false;
 51 }
 52 
 53 //打印队
 54 void print(seqQueue &q)
 55 {
 56     int f = q.front, r = q.rear;
 57     while (f != r)
 58     {
 59         f = (f + 1) % maxsize;
 60         cout << q.queue[f] << ", ";
 61     }
 62     cout << endl;
 63 }
 64 
 65 //打印说明
 66 void showHelp(void)
 67 {
 68     cout << "\n\n\n\n";
 69     cout << "\t\t\t 队列子系统\n";
 70     cout << "\t\t*******************************\n";
 71     cout << "\t\t*        1----进 队 列　  　　*\n";
 72     cout << "\t\t*        2----出 队 列　　　　*\n";
 73     cout << "\t\t*        3----队列空否　　　　*\n";
 74     cout << "\t\t*        4----显示队列　　　　*\n";
 75     cout << "\t\t*        0----返　　回　　　　*\n";
 76     cout << "\t\t*******************************\n";
 77     cout << "\t\t 请选择菜单项0－4：";
 78 }
 79 
 80 int main()
 81 {
 82     seqQueue q;
 83     init(q);
 84     datatype e;
 85     int k = 0;
 86     bool flag = true;
 87     do
 88     {
 89         showHelp();
 90         cin >> k;
 91         switch (k)
 92         {
 93         case 1:    //入队
 94             cout << endl << "请输入要进队的数据 ";
 95             cin >> e;
 96             enQueue(q, e);
 97             break;
 98         case 2:    //出队
 99             cout << delQueue(q);
100             break;
101         case 3:    //判断队空与否
102             flag = isEmpty(q);
103             if (flag == true)
104                 cout << "队空";
105             else
106                 cout << "队不空";
107         case 4:    //打印队列
108             cout << "队中元素如下" << endl;
109             print(q);
110             break;
111         default:
112             break;
113         }
114     } while (k != 0);
115     return 0;
116 }