Java基础-面向对象1：练习题目

1.利用面向对象的编程方法，设计类Circle计算圆的面积

//利用面向对象的编程方法，设计类Circle计算圆的面积



public class TestCircle {
    public static void main(String[] args) {
        Circle c1 = new Circle();
        c1.Radius = 2;
        double Area = c1.findArea();
        System.out.println(Area);
    }
}


public class Circle {

        int Radius;

        public double findArea(){
            return 3.14 * Radius * Radius;
            }
}

2.题目

+ 表示修饰符为 public

public class TestPerson {
    public static void main(String[] args) {

        Person p1 = new Person();
        Person p2 = new Person();
        p1.name = "Lily";
        p1.age = 22;
        p1.sex = 1;

        p2.name = "Lucy";
        p2.age = 23;
        p2.sex = 0;

        p1.showAge();
        p1.study();
        p1.addAge(5);
        p1.showAge();
        p1.study();

        System.out.println("---------------");

        p2.showAge();
        p2.study();
        p2.addAge(5);
        p2.showAge();
        p2.study();
    }
}


public class Person {
    public String name;
    public int age;
    public int sex;

public void study(){
    System.out.println("Studying");
    };
public void showAge(){
    System.out.println("age:"+ age);
    };
public void addAge(int i){
    age = age + i;
    };
}