HashSet ——学生姓名&成绩

 Implement HashSet to store ‘n’ records of students ( Name, Percentage). Write a menu driven program to :

1. Add student

2. Display details of all students

3. Search student

4. Find out highest marks

 

package Aug11.Collection;

import java.util.*;

public class Test4 {
    public static Set set = new HashSet();

    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);

        while (true) {
            System.out.println("---------------------");
            System.out.println("1. Add student");
            System.out.println("2. Display details of all students");
            System.out.println("3. Search student");
            System.out.println("4. Find out highest marks");
            System.out.println("5. Exit");
            System.out.println("---------------------");
            int n = reader.nextInt();
            switch (n) {
            case 1:
                addStu();
                break;
            case 2:
                displayAllStu();
                break;
            case 3:
                searchStu();
                break;
            case 4:
                findHighestMarks();
                break;
            case 5:
                Exit();
                break;
            }
        }

    }

    private static void Exit() {
        System.out.println("Exit Success!");
        System.exit(0);

    }

    private static void findHighestMarks() {
        Student stu;
        int max = 0;
        Iterator itr = set.iterator();
        while (itr.hasNext()) {
            stu = (Student) itr.next();
            if (stu.getPercentage() > max) {
                max = stu.getPercentage();
            }

        }
        System.out.println("The  highest mark is " + max);

    }

    private static void searchStu() {
        Scanner reader = new Scanner(System.in);
        boolean flag = false;
        System.out.println("Enter the student's name:");
        String name = reader.nextLine();
        Iterator itr = set.iterator();
        while (itr.hasNext()) {
            Student stu = (Student) itr.next();
            if (stu.getName().equals(name)) {
                System.out.println(stu.getName() + ":" + stu.getPercentage());
                return;
            } else{
                flag=false;
            }
        }
        if(!flag)
        System.out.println("There has no such person");
    }

    private static void displayAllStu() {
        System.out.println("The information of all students:");
        Iterator itr = set.iterator();
        while (itr.hasNext()) {
            Student stu = (Student) itr.next();
            System.out.println(stu.getName() + ":" + stu.getPercentage());
        }
    }

    private static void addStu() {
        Scanner reader = new Scanner(System.in);
        System.out.println("Enter student's name:");
        String name = reader.nextLine();
        System.out.println("Enter student's percentage:");
        int percentage = reader.nextInt();
        Student stu = new Student(name, percentage);
        set.add(stu);
    }

}

// Student class

class Student {
    String name;
    int percentage;
    public Student(){
        
    }
    public Student(String name, int percentage) {
        this.name = name;
        this.percentage = percentage;

    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPercentage() {
        return percentage;
    }

    public void setPercentage(int percentage) {
        this.percentage = percentage;
    }

}