queue.java

一个java源代码包

//使用数组模拟队列
//该程序实现了队列的存取

import java.io.*;


import java.io.*; // for I/O
////////////////////////////////////////////////////////////////
class Queue
{
	private int maxSize;
	private int[] queArray;
	private int front;
	private int rear;
	private int nItems;
//--------------------------------------------------------------
	public Queue(int s) // constructor
	{
		maxSize = s;
		queArray = new int[maxSize];
		front = 0;
		rear = -1;
		nItems = 0;
	}
//--------------------------------------------------------------
	public void insert(int j)  // put item at rear of queue
	{
		if(rear == maxSize-1)  // deal with wraparound
		rear = -1;
		queArray[++rear] = j;  // increment rear and	insert
		nItems++; 			   // one more item
	}
//--------------------------------------------------------------
	public int remove()        // take item from front of queue
	{
		int temp = queArray[front++]; // get value and incr front
		if(front == maxSize)    // deal with wraparound
		front = 0;
		nItems--;             // one less item
		return temp;
	}
//--------------------------------------------------------------
	public int peekFront() // peek at front of queue
	{
		return queArray[front];
	}
//------------------------------------------------------------
	public boolean isEmpty() // true if queue is empty
	{
		return (nItems==0);
	}
//--------------------------------------------------------------
	public boolean isFull() // true if queue is full
	{
		return (nItems==maxSize);
	}
//--------------------------------------------------------------
	public int size() // number of items in queue
	{
		return nItems;
	}
//--------------------------------------------------------------
} // end class Queue
////////////////////////////////////////////////////////////////
class QueueApp
{
	public static void main(String[] args)throws Exception
	{
		Queue theQueue = new Queue(8); // queue holds 5 items
		for(int i=0;i<8;i++)
		{
			String str;
			InputStreamReader ir;
			BufferedReader in;
			ir=new InputStreamReader(System.in);
			in=new BufferedReader(ir);
			str=in.readLine();
			int n=Integer.parseInt(str);
			theQueue.insert(n);
			if(i==3)
			{
				int m=0;
				while(!theQueue.isEmpty()&&m<3)
				{
					theQueue.remove();
					m++;
				}
			}
		}
		
		
		
		/*theQueue.insert(10);   // insert 4 items
		theQueue.insert(20);
		theQueue.insert(30);
		theQueue.insert(40);
		theQueue.remove();     // remove 3 items
		theQueue.remove();     // (10, 20, 30)
		theQueue.remove();
		theQueue.insert(50);   // insert 4 more items
		theQueue.insert(60);   // (wraps around)
		theQueue.insert(70);
		theQueue.insert(80);*/
		while( !theQueue.isEmpty() ) // remove and display
		{ // all items
			int n = theQueue.remove(); // (40, 50, 60, 70, 80)
			System.out.print(n);
			System.out.print(" ");
		}
		System.out.println("");
	} // end main()
} // end class QueueApp