循环队列的实现

#include <iostream> #include <string> #include <cassert> using namespace std; /*用数组实现循环队列 (1)、设一标志位以区别队列是“空”还是“满” (2)、少用一空间，约定“队列头指针在队尾指针的下一位置”上作为队列呈“满”状态的标志 */ template <typename T> class MyDeque { public: MyDeque(int n= 10);//构造函数 bool EnterQueue(T element);//向队列插入元素 bool DeleteQueue(int &element);//从队列弹出元素 int QueueLength();;//返回队列的长度 private: int front; //对头指针 int rear; //队尾指针 T *base; //动态分配的内存指针 int maxsize; //最大队列长度 }; template <typename T> MyDeque<T>::MyDeque(int n) { base = (T*)new T[n]; assert(base != NULL); memset(base, 0, n); front = rear = 0; //队头和队尾指针分别指向地一个元素 maxsize = n; } template <typename T> bool MyDeque<T>::EnterQueue(T element) { if ((rear + 1) % maxsize == front) //判断队列是否满 { return false; } else { base[rear] = element; rear = (rear+1) % maxsize; return true; } } template <typename T> bool MyDeque<T>::DeleteQueue(int &element) { if (front == rear)//判断队列是否为空 { return false; } else { element = base[front]; base[front] = 0; front = (front + 1) % maxsize; return true; } } template <typename T> int MyDeque<T>::QueueLength() { return (rear - front + maxsize) % maxsize; } int main() { MyDeque<int> my(10); int i; for (i=0 ;i<5; i++) { my.EnterQueue(i+1); } cout<<"队列长度:"<<my.QueueLength()<<endl; int element; for (i=0; i<5; i++) { my.DeleteQueue(element); printf("第%d个元素为%d/n", i+1, element); } cout<<"队列长度:"<<my.QueueLength()<<endl; }