queue.cpp

c++模板小实验

#include <iostream.h>
template<class T>
class queue
{public:
    queue(int = 50);          
    ~queue( )   {      delete [] sqPtr; }    
    int enqueue(const T&);     //入队
    int dlqueue(T&);            //出队
    int gethead(T&);
    int isempty() const { return front == rear;    } //注意
    int isfull() const {return rear == size - 1; }
private:
    int front,rear,size;
    T *sqPtr;
}; 
template<class T>
queue<T>::queue(int s)
{    size = s > 0 && s < 1000 ? s : 50;  
    front=rear=-1;     //注意
    sqPtr = new T[size];}
//input an element into the queue
template<class T>
int queue<T>::enqueue(const T &item)
{
	if( !isfull( ) )
	{	sqPtr[++rear]=item;
	    return 1;
    }
	return 0;
}       

//output an element off the queue
template<class T>
int queue<T>::dlqueue(T &Value)
{
     if ( !isempty( ) )
     {
         Value = sqPtr[++front];
         return Value;
     }
     return 0;
}
//get the head of the queue
template<class T>
int queue<T>::gethead(T &head)
{
	if ( !isempty( ) )
	{    
		head=sqPtr[++front];
        front--;
	    return head;
	}
	return 0;
}

void main( )
{  
     queue<int> intqueue(5); 
	 int a=1;
     cout << "enqueue!" << endl;
     while ( intqueue.enqueue(a) ) {cout <<  a << " ";  a += 1;}
     cout << endl << "queue is full. Cannot input " << a << endl;
	 intqueue.gethead(a);
	 cout<<"the head of the queue is : "<< a <<endl;
     cout << "dlqueue!" << endl;
     while ( intqueue.dlqueue(a)  ) cout << a << " ";
     cout << endl << "queue is empty. Cannot output " << endl;
}