Java数组模拟队列

你的名字 2024-04-18 16:53 1阅读 0赞

### 文章目录 ###

*   *  1. 数组模拟队列
     *  2. 数组模拟环形队列

## 1. 数组模拟队列 ##

*  缺点

> 数组不能复用

package com.cds.queue;
    
    import java.util.Scanner;
    
    public class QueueArray { 
    	public static void main(String[] args) { 		
    		Scanner sc = new Scanner(System.in);
    		System.out.println("请输入队列的长短");
    		int maxSize = sc.nextInt();
    		Queuearr queue = new Queuearr(maxSize);
    		boolean flag = true;
    		char key = ' ';
    		while(flag) { 
    			System.out.println("-----meau-------");
    			System.out.println("s-show:输入s打印队列");
    			System.out.println("a-add：输入a添加数据");
    			System.out.println("g-get：输入g弹出一个数据");
    			System.out.println("h-head：输入h获取头数据");
    			System.out.println("e-exit：输入e退出");
    			System.out.println("---------------");
    			//接受一个字符
    			key = sc.next().charAt(0);
    			switch (key) { 
    			case 's':
    				queue.showQueue();
    				break;
    			case 'a':
    				System.out.println("请输入要添加的数字");
    				try { 
    					int data = sc.nextInt();
    					queue.add(data);
    				} catch (Exception e) { 
    					e.printStackTrace();
    				}
    				break;
    			case 'g':
    			System.out.println(queue.getQueue());
    				break;
    			case 'h':
    				queue.headQueue();
    				break;	
    			case 'e':
    				flag = false;
    				break;
    			default:
    				break;	
    			}
    			
    		}
    		System.out.println("成功推出");
    		
    	}
    
    }
    
    
    class Queuearr{ 
    	private int maxSize;
    	private int fornt;
    	private int rear;
    	private int[] arr;
    	
    	public Queuearr(int maxSize) { 
    		this.maxSize = maxSize;
    		//指向队列头前一个元素【不包含】
    		this.fornt = -1;	
    		//指向队列尾的最后一个元素【包含】
    		this.rear = -1;
    		arr = new int[maxSize];
    	}
    	
    	public boolean isEmpty() { 
    		return fornt == rear;
    	}
    	
    	public boolean isFull() { 
    		return fornt == maxSize - 1;
    	}
    	
    	public void add(int data) { 
    		if(isFull()) { 
    			System.out.println("队列已满，不可添加元素");
    		}
    		arr[++rear] = data;
    
    	}
    	
    	public int getQueue() { 
    		if(isEmpty()) { 
    			throw new RuntimeException("队列为空，无可弹出元素");
    		}
    		fornt++;
    		return arr[fornt];
    	}
    	
    	public void showQueue() { 
    		if(isEmpty()) { 
    			System.out.println("队列为空，无元素");
    		}else { 
    			for (int i = 0; i < arr.length; i++) { 
    				System.out.printf("%d\t",arr[i]);
    			}
    			System.out.println();
    		}
    		
    	}
    	
    	public int headQueue() { 
    		if(isEmpty()) { 
    			throw new RuntimeException("数组为空");
    		}
    		return arr[fornt+1];
    	}
    	
    }

## 2. 数组模拟环形队列 ##

package com.cds.queue;
    
    import java.util.Scanner;
    
    public class CircleArrayQueue { 
    	public static void main(String[] args) { 
    		Scanner sc = new Scanner(System.in);
    		System.out.println("请输入队列的长短");
    		int maxSize = sc.nextInt();
    		circleArrayQueueDemo queue = new circleArrayQueueDemo(maxSize);
    		boolean flag = true;
    		char key = ' ';
    		while(flag) { 
    			System.out.println("-----meau-------");
    			System.out.println("s-show:输入s打印队列");
    			System.out.println("a-add：输入a添加数据");
    			System.out.println("p-pop：输入p弹出一个数据");
    			System.out.println("h-head：输入h获取头数据");
    			System.out.println("e-exit：输入e退出");
    			System.out.println("---------------");
    			//接受一个字符
    			key = sc.next().charAt(0);
    			switch (key) { 
    			case 's':
    				queue.showQueue();
    				break;
    			case 'a':
    				System.out.println("请输入要添加的数字");
    				int data = sc.nextInt();
    				try { 
    					queue.add(data);
    				} catch (Exception e) { 
    					e.printStackTrace();
    				}
    				break;
    			case 'p':
    			System.out.println(queue.pop());
    				break;
    			case 'h':
    				queue.getHead();
    				break;	
    			case 'e':
    				flag = false;
    				break;
    			default:
    				break;	
    			}
    			
    		}
    		
    		
    		
    		
    	}
    }
    
    class circleArrayQueueDemo{ 
    	private int head;
    	private int tail;
    	private int maxSize;
    	private int[] arr;
    	
    	public circleArrayQueueDemo(int maxSize) { 
    		this.maxSize = maxSize;
    		arr = new int[maxSize];
    		head = tail = 0;
    	}
    	
    	/** * 判断队列是否为空 */
    	public boolean isEmpty() { 
    		return head == tail;
    	}
    	
    	/** * 判断队列是否满了 */
    	public boolean isFull() { 
    		return (tail + 1) % maxSize == head;
    	}
    	
    	/** * 给队列中添加元素 */
    	public void add(int data) { 
    		if(isFull()) { 
    			System.out.println("队列已满，无法添加");
    			return;
    		}else { 
    			arr[tail] = data;
    			tail = (tail +1	) % maxSize;
    		}
    		
    	}
    	
    	/** * 从队列中取出元素 */
    	public int pop() { 
    		if(isEmpty()) { 
    			System.out.println("队列为空");
    			throw new RuntimeException();
    		}
    		int tmp = arr[head];
    		head = (head + 1) % maxSize;
    		return tmp;
    	}
    	
    	/** * 队列有效数据个数 */
    	public int size() { 
    		return (tail - head + maxSize) % maxSize;
    	}
    	
    	/** * 遍历打印数组 */
    	public void showQueue() { 
    		if(isEmpty()) { 
    			System.out.println("队列为空");
    			return;
    		}
    		for (int i =head; i < head + size(); i++) { 
    			System.out.printf("a[%d]=%d、",i % maxSize ,arr[i % maxSize]);
    		}
    		System.out.println();
    
    	}
    	
    	public int getHead() { 
    		if(isEmpty()) { 
    			System.out.println("队列为空，没有头元素");
    			throw new RuntimeException();
    		}
    		return arr[head];
    	}
    	
    	
    }