javaSE_07Java中类和对象-封装特性--练习

1.编写封装一个学生类,有姓名,有年龄,有性别,有英语成绩,数学成绩,语文成绩,一个学生类,我们关注姓名,年龄,学历等信息,要求年龄必须在19-40岁之间,默认为19,学历必须是大专,本科,研究生这几个值的范围内,默认为大专。创建对象,测试其相关方法

类的创建:

/**
 * 3.编写一个学生类,我们关注姓名,年龄,学历等信息,
 * 要求年龄必须在19-40岁之间,默认为19,学历必须是大专,
 * 本科,研究生这几个值的范围内,默认为大专。创建对象,测试其相关方法
 * @author Administrator
 *
 */
public class Student {
    private String name;
    private int age;
    private String education;

    //set get
    public void setName(String name){
        this.name=name;//这里必须加this,因为出现了局部变量和成员变量重名,必须指明name是哪个,下面同理
    }
    public String getName(){
        return this.name;
    }
    public void setAge(int age){
        if(age<19||age>40){
            this.age=19;
        }else{
            this.age=age;
        }   
    }
    public int getAge(){
        return this.age;
    }
    public void setEducation(String education){
        if(education.equals("大专")||education.equals("本科")||education.equals("研究生")){
            this.education=education;
        }else{
            this.education="大专";
        }
    }
    public String getEducation(){
        return this.education;
    }

}

类的测试:


public class StudentTest {
    public static void main(String[] args){
        //1,创建对象
        Student student=new Student();
        //2,赋值
        student.setName("张三");
        student.setAge(28);
        student.setEducation("本科");
        //3,获取
        System.out.println(student.getName());
        System.out.println(student.getAge());
        System.out.println(student.getEducation());

        System.out.println();
        //再创建一个对象.用于验证不符合条件情况
        Student student2=new Student();
        student2.setName("李四");
        student2.setAge(10);
        student2.setEducation("博士");
        System.out.println(student2.getName());
        System.out.println(student2.getAge());
        System.out.println(student2.getEducation());
    }
}

2.封装方法,求总分,平均分,最高分,最低分,以及打印学生的信息。创建对象,测试其相关方法

类的创建:

/**
 * 4.封装一个学生类,有姓名,有年龄,有性别,有英语成绩,数学成绩,
 * 语文成绩,封装方法,求总分,平均分,最高分,最低分,
 * 以及打印学生的信息。创建对象,测试其相关方法
 * @author Administrator
 *
 */
public class Student2 {
    private String name;
    private int age;
    private String sex;
    private double english;
    private double math;
    private double chinese;

    //set get
    public void setName(String name){
        this.name=name;
    }
    public String getName(){
        return this.name;
    }
    public void setAge(int age){
        this.age=age;

    }
    public int getAge(){
        return this.age;
    }
    public void setSex(String sex){
        this.sex=sex;
    }
    public String getSex(){
        return this.sex;
    }
    public void setEnglish(double english){
        this.english=english;
    }
    public double getEnglish(){
        return this.english;
    }
    public void setMath(double math){
        this.math=math;
    }
    public double getMath(){
        return this.math;
    }
    public void setChinese(double chinese){
        this.chinese=chinese;
    }
    public double getChinese(){
        return this.chinese;
    }

    //构造函数实现直接给属性赋值
    public Student2(){}

    public Student2(String name,int age,String sex,double english,double math,double chinese){
        this.setName(name);
        this.setAge(age);
        this.setSex(sex);
        this.setEnglish(english);
        this.setMath(math);
        this.setChinese(chinese);
    }



    //getSum
    public double getSum(){
        return this.english+this.math+this.chinese;
    }
    //getAverage
    public double getAverage(){
        return this.getSum()/3;
    }
    //getMax
    public double getMax(){
        double max=this.english>this.math?this.english:this.math;
        max=max>this.chinese?max:this.chinese;
        return max;
    }
    //getMin
    public double getMin(){
        double min=this.english<this.math?this.english:this.math;
        min=min<this.chinese?min:this.chinese;
        return math;
    }


}

类的测试:


public class Student2Test {
    public static void main(String[] args){
        Student2 student=new Student2("张飞",99,"男",88,77,79);


        System.out.println(student.getName()+"成绩分析如下:");
        System.out.println("总分:"+student.getSum());
        System.out.println("平均分:"+student.getAverage());
        System.out.println("最高分分:"+student.getMax());
        System.out.println("最低分:"+student.getMin());

        System.out.println();
        //也可以和上一个例题一个个赋值
        Student2 student2=new Student2();
        student2.setName("刘备");
        student2.setAge(78);
        student2.setEnglish(99);
        student2.setMath(88);
        student2.setChinese(89);
        System.out.println(student2.getName()+"成绩分析如下:");
        System.out.println("总分:"+student2.getSum());
        System.out.println("平均分:"+student2.getAverage());
        System.out.println("最高分分:"+student2.getMax());
        System.out.println("最低分:"+student2.getMin());
    }
}

3.编写一个随机点名系统,两个功能,一个是抽取学员回答问题,一个是记录学员被命中的次数

类的创建:

package day09;
/**
 * 编写一个随机点名系统,两个功能,
 * 一个是抽取学员回答问题,一个是记录学员被命中的次数
 * @author Administrator
 *
 */
public class NameSystem {
    private String name;
    private int times;

    //构造方法
    public NameSystem(){

    }
    public NameSystem(String name,int times){
        this.setName(name);
        this.setTimes(times);
    }
    //set get
    public void setName(String name){
        this.name=name;
    }
    public void setTimes(int times){
        this.times=times;
    }
    public String getName(){
        return this.name;
    }
    public int getTimes(){
        return this.times;
    }
}

类的调用:

package day09;
import java.util.Scanner;
public class NameSystemTest {
    public static void main(String[] args){
        //1,创建对象
        /*
        NameSystem[] persons=new NameSystem[5];
        persons[0].setName("张三");
        persons[0].setTimes(0);
        //动态赋值
        persons[0]=new NameSystem("小李",0);
        persons[1]=new NameSystem("小张",0);
        persons[2]=new NameSystem("小王",0);
        persons[3]=new NameSystem("小明",0);
        persons[4]=new NameSystem("小刚",0);*/
        //静态赋值
        NameSystem[] persons={new NameSystem("小李",0),new NameSystem("小张",0),
                new NameSystem("小王",0),new NameSystem("小明",0),new NameSystem("小刚",0)};
        Scanner input=new Scanner(System.in);
        String isContinue;
        //2,点名
        do{
            int index=(int)(Math.random()*persons.length);
            System.out.println("本次抽中的学员是:"+persons[index].getName());
            persons[index].setTimes(persons[index].getTimes()+1);
            System.out.println("继续请输入y,其他任意键退出");
            isContinue=input.next();
        }while(isContinue.equals("y"));
        System.out.println("本次点名的结果统计:");
        for(NameSystem p:persons){
            System.out.println(p.getName()+":"+p.getTimes());
        }

        //关闭io流
        input.close();

    }
}
原文地址:https://www.cnblogs.com/TCB-Java/p/6770146.html