9.20

学生信息管理系统 基本的数组增删改查
import java.util.Scanner;

class student{
private String stunumber;
private String name;
private int age;
private boolean sex;
public double score;
public student() {
}

public student(String stunumber, String name, int age, boolean sex, double score) {
    this.stunumber = stunumber;
    this.name = name;
    this.age = age;
    this.sex = sex;
    this.score = score;
}

public String getStunumber() {
    return stunumber;
}

public void setStunumber(String stunumber) {
    this.stunumber = stunumber;
}

public String getName() {
    return name;
}

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

public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

public boolean isSex() {
    return sex;
}

public void setSex(boolean sex) {
    this.sex = sex;
}

public double getScore() {
    return score;
}

public void setScore(double score) {
    this.score = score;
}
public void display() {
    System.out.println("学号: " + stunumber + " 姓名: " + name + " 年龄: " + age + " 性别: " + (sex ? "女" : "男") + " 成绩: " + score);
}

}
public class StudentManager {
private static student s1[] = new student[5];
private static int count = 0;
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (true) {
System.out.println("");
System.out.println(" 石家庄铁道大学软件工程系学生信息管理系统");
System.out.println("");
System.out.println(" 1、遍历输出学生信息；");
System.out.println(" 2、新学生信息录入；");
System.out.println(" 3、删除学生信息；");
System.out.println(" 4、修改学生信息；");
System.out.println(" 5、查询学生信息；");
System.out.println(" 6、退出");
System.out.println("***************************************************************");
System.out.println("请输入选择：");
String choose = sc.next();

        switch (choose) {
            case "1":
                showStudent();
                break;
            case "2":
                System.out.print("请输入学号：");
                String stunumber = sc.next();
                System.out.print("请输入姓名：");
                String name = sc.next();
                System.out.print("请输入年龄：");
                int age = sc.nextInt();
                System.out.print("请输入性别（男生为false，女生为true）：");
                boolean sex = sc.nextBoolean();
                System.out.print("请输入成绩：");
                double score = sc.nextDouble();
                addStudent (stunumber,name,age,sex,score);
                break;
            case "3":
                System.out.print("请输入要删除的学号：");
                stunumber = sc.next();
                deleteStudent(stunumber);
                break;
            case "4":
                System.out.print("请输入要修改的学号：");
                stunumber = sc.next();
                System.out.print("请输入新的姓名：");
                name = sc.next();
                System.out.print("请输入新的年龄：");
                age = sc.nextInt();
                System.out.print("请输入新的性别（男生输入false，女生输入true）：");
                sex = sc.nextBoolean();
                System.out.print("请输入新的成绩：");
                score = sc.nextDouble();
                updateStudent (stunumber,name,age,sex,score);
                break;
            case "5":
                System.out.print("请输入要查询的学号：");
                stunumber = sc.next();
                selectStudent(stunumber);
                break;
            case "6":
                System.exit(0);
            default:
                System.out.println("没有这个选项");
                break;
        }
    }
}


public static void showStudent(){
    if(count == 0){
        System.out.println("没有学生信息");
    }
    for (int i = 0; i < count; i++) {
        s1[i].display();
    }
}


public static void addStudent (String stunumber,String name,int age,boolean sex,double score){
    for (int i = 0; i < count; i++) {
        if (s1[i].getStunumber().equals(stunumber)) {
            System.out.println("学号已存在");
            return;
        }
    }
    if (count < 5) {
        s1[count++] = new student(stunumber, name, age, sex, score);
        System.out.println("添加成功");
    } else {
        System.out.println("学生信息已满，无法添加新学生");
    }
}


public static void deleteStudent(String stunumber){
    for (int i = 0; i < count; i++) {
        if (s1[i].getStunumber().equals(stunumber)) {
            s1[i] = null;
            System.out.println("删除成功");
            for (int j = i; j < count - 1; j++) {
                s1[j] = s1[j + 1];
            }
            s1[--count] = null;
            return;
        }
    }
    System.out.println("未找到该学号的学生信息");
}


public static void updateStudent (String stunumber,String name,int age,boolean sex,double score){
    for (int i = 0; i < count; i++) {
        if (s1[i].getStunumber().equals(stunumber)) {
            s1[i].setName(name);
            s1[i].setAge(age);
            s1[i].setSex(sex);
            s1[i].setScore(score);
            System.out.println("修改成功");
            return;
        }
    }
    System.out.println("未找到该学号的学生信息");
}


public static void selectStudent(String stunumber){
    for (int i = 0; i < count; i++) {
        if (s1[i].getStunumber().equals(stunumber)) {
            s1[i].display();
            return;
        }
    }
    System.out.println("未找到该学号的学生信息");
}

}