第一题

image.png

public class Circle {
private int r;
Circle(){

    };
    public int getR(){
        return r;
    }
        public void  setR(int r){
            this.r=r;

        }
        public void showArea(){
        double s=3.14*r*r;
        System.out.println("半径为："+r+",面积为："+s);

    }
    public  void showPerimeter(){
      double l=3.14*2*r;
    System.out.println("半径为："+r+"周长为："+l);

}

}
//TestCircle
public class TestCircle {
public static void main(String[] args) {
Circle circle=new Circle();
circle.setR(5);
System.out.println(circle.getR());
circle.showArea();
circle.showPerimeter();
}
}

image.png

public class MyDate {
private int year;
private int month;
private int day;

MyDate(int year, int month, int day) {
    this.year=year;
    this.month=month;
    this.day=day;
}

public int getYear() {
    return year;
}

public void setYear(int year) {
    this.year = year;
}

public int getMonth() {
    return month;
}

public void setMonth(int month) {
    this.month = month;
}

public int getDay() {
    return day;
}

public void  setDay(int day) {
    this.day = day;
}

public void showData() {
    System.out.println("日期：" + year + "年" + month + "月" + day + "日");

}

public boolean isBi(boolean flag) {
    if (year % 100 != 0 && year % 4 == 0) {
        flag = true;
        System.out.println(year + "是闰年");
    }
    if (year % 100 == 0 && year % 400 == 0) {
        flag = true;
        System.out.println(year + "是闰年");
        return flag;}
    System.out.println(year+"不是闰年");
    return flag;
    }
}

测试类
public class TestData {
public static void main(String[] args) {
MyDate mydate=new MyDate(1993,3,4);
mydate.showData();
mydate.isBi(true);
}
}

image.png

public class Card {
private String Color;
private String point;
Card(){}
Card(String Color ,String point){
this.Color=Color;
this.point=point;

}
public void showCard(){
    System.out.println(Color+point);
}

}
public class TestCard {
public static void main(String[] args) {
Card card=new Card("黑桃","A");
card.showCard();
}
}