java链式队列实现学生管理系统

package 学生信息管理;

import java.util.Scanner;

class Queue {
	//链结点
	Student front;
	Student rear; 
//		public LQ() {}
}

public class Student {
	String name;
	int score;
	int xuehao;
	private Student next;
	private int size;
	
	//初始化操作
	public void init(Queue q){
		this.size = 0;
		q.front = q.rear = null;
	}
	
	//判队空
	public boolean isEmpty(Queue q) {
		if((q.front == q.rear)&&(size == 0)) {
			return true;
		}else {
			return false;
		}
	}
	
	//入队
	public void add(Queue q) {
		Scanner sc = new Scanner(System.in);
		Student stu = new Student();
		System.out.println("请输入该学生的信息：");
		System.out.print("姓名：");
		String name=sc.next();
		stu.name = name;
        System.out.print("成绩：");
		int score=sc.nextInt ();
		stu.score = score;
		System.out.print("学号：");
		int xuehao=sc.nextInt ();
		stu.xuehao = xuehao;
		if(isEmpty(q)) {
			q.front = stu;
			q.rear = stu;
			size++;
		}else {
			q.rear.next = stu;
			q.rear = stu;
			size++;
		}
	}
	
	//出队
	public void pop(Queue q) {
		if(isEmpty(q)) {
			System.out.println("队列为空！");
		}else {
			Student stu = q.front;
			q.front = stu.next;
			size--;
			System.out.println("出队成功！");
		}
	}
	
	//插入
	public void insert(Queue q) {
		System.out.println("您想在第几个学生后插入？：");
		Scanner sc = new Scanner(System.in);
		int index = sc.nextInt();
		if(index<=0 || index>size) {
			System.out.println("序号非法，插入失败！");
		}
		Student stu = new Student();
		System.out.println("请输入该学生的信息：");
		System.out.print("姓名：");
		String name=sc.next();
		stu.name = name;
        System.out.print("成绩：");
		int score=sc.nextInt ();
		stu.score = score;
		System.out.print("学号：");
		int xuehao=sc.nextInt ();
		stu.xuehao = xuehao;
		Student s = q.front;
		for(int i=1;i<index;i++) {
			s = s.next;
		}
		stu.next = s.next;
		s.next = stu;
		System.out.println("操作成功！");
		size++;
	}
	
	//删除
	public void del(Queue q) {
		System.out.println("请输入想删除的学生学号：");
		Scanner sc = new Scanner(System.in);
		int xh = sc.nextInt();
		Student s = q.front;
		for(int i=1;i<size;i++) {
			if((i == 1)&&(s.xuehao == xh)) {
				System.out.println("查找到该学生："+"姓名："+s.name+" 成绩："+s.score+" 学号："+s.xuehao);
				pop(q);
				size--;
				break;
			}else if(s.next.xuehao == xh){
				System.out.println("查找到该学生："+"姓名："+s.next.name+" 成绩："+s.next.score+" 学号："+s.next.xuehao);
				s.next = s.next.next;
				System.out.println("删除成功！");
				size--;
				break;
			}else if(s == null) {
				System.out.println("未找到该学号！");
			}else {
				s = s.next;
			}
		}
	}
	
	//修改
	public void change(Queue q) {
		System.out.println("请输入想修改的学生学号：");
		Scanner sc = new Scanner(System.in);
		int xh = sc.nextInt();
		Student s = q.front;
		for(int i=1;i<=size;i++) {
			if(s.xuehao == xh){
				System.out.println("查找到该学生："+"姓名："+s.name+" 成绩："+s.score+" 学号："+s.xuehao);
				System.out.print("姓名：");
				String name=sc.next();
				s.name = name;
                System.out.print("成绩：");
				int score=sc.nextInt ();
				s.score = score;
				System.out.print("学号：");
				int xuehao=sc.nextInt ();
				s.xuehao = xuehao;
				System.out.println("修改成功！");
				break;
			}else if(s.next == null) {
				System.out.println("该学生不存在！");
			}else {
				s = s.next;
			}
		}
	}
	
	//查找
	public void check(Queue q) {
		System.out.println("请输入想查找的学生学号：");
		Scanner sc = new Scanner(System.in);
		int xh = sc.nextInt();
		Student s = q.front;
		for(int i=1;i<=size;i++) {
			if(s.xuehao == xh){
				System.out.println("查找到该学生：");
				System.out.println("姓名："+s.name+" 成绩："+s.score+" 学号："+s.xuehao);
				break;
			}else if(s == null) {
				System.out.println("该学生不存在！");
			}else {
				s = s.next;
			}
		}
	}
	
	//打印
	public void print(Queue q) {
		Student s = q.front;
		while(s != null) {
			System.out.println("姓名："+s.name+" 成绩："+s.score+" 学号："+s.xuehao);
			s = s.next;
		}
		if(q.front == null) {
			System.out.println("队列为空！");
		}
	}
	
	//排序
	public void sort(Queue q) {
		Student s1 = q.front;
		while(s1 != null) {
			Student s2 = q.front;
			while(s2 != null) {
				if(s2.score>s1.score) {
					int tem1 = s2.score;
					s2.score =  s1.score;
					s1.score = tem1;
					int tem2 = s2.xuehao;
					s2.xuehao =  s1.xuehao;
					s1.xuehao = tem2;
					String tem3 = s2.name;
					s2.name =  s1.name;
					s1.name = tem3;
				}
				s2 = s2.next;
			}
			s1 = s1.next;
		}
		print(q);
	}
	public static void main(String[] args) {
		Queue q = new Queue();
		Student stu = new Student();
		stu.init(q);
		System.out.println("学生队列基本功能菜单");
		System.out.println("=====================");
		System.out.println("1.学生信息入队");
		System.out.println("2.学生信息出队");
		System.out.println("3.插入学生信息");
		System.out.println("4.删除学生信息");
		System.out.println("5.修改学生信息");
		System.out.println("6.查找学生信息");
		System.out.println("7.打印学生信息");
		System.out.println("8.将学生按成绩由高到低排序");
		System.out.println("9.退出学生信息队列操作");
		System.out.println("=====================");
		System.out.print("请选择功能：");
		while(true) {
			Scanner sc = new Scanner(System.in);
			int num = sc.nextInt();
			if(num==1) {
				stu.add(q);
				System.out.println("入队成功！");
			}else if(num==2) {
				stu.pop(q);
			}else if(num==3) {
				stu.insert(q);
			}else if(num==4) {
				stu.del(q);;
			}else if(num==5) {
				stu.change(q);
			}else if(num==6) {
				stu.check(q);;
			}else if(num==7) {
				stu.print(q);;
			}else if(num==8) {
				stu.sort(q);;
			}else if(num==9) {
				break;
			}
		}
	}
}