第六题:
//创建一个名为“Shape”的抽象类
public abstract class Shape {
//抽象方法计算周长
public abstract double getGirth(int i);
//抽象方法计算面积
public abstract double getArea(int i);
}
public class Circle extends Shape {
@Override
public double getGirth(int i) {
//圆的周长
return 2*3.14*i;
}
@Override
public double getArea(int i) {
//圆的面积
return 3.14*i*i;
}
测试类如下:public class Test {
public static void main(String[] args) {
Circle circle=new Circle();
Scanner sc=new Scanner(System.in);
System.out.println("请输入半径:");
int i=sc.nextInt();
System.out.println("圆的周长为"+circle.getArea(i));
System.out.println("圆的周长为"+circle.getGirth(i));
}
}
第五题:
(1)
public abstract class Animal {
float size;
String breed;
abstract void eat();
abstract void roam();
abstract void mokenoise();
}
(2)
public interface Pet {
void feed();
void play();
}
(3)
public class Dog extends Animal implements Pet{
public Dog(){ }
public Dog(float s){
size=s;
};
@Override
void eat() {
System.out.println("狗正在eat");
}
@Override
void roam() {
System.out.println("狗正在roam");
}
@Override
void mokenoise() {
System.out.println("狗正在mokenoise");
}
@Override
public void feed() {
System.out.println("狗正在 feed");
}
@Override
public void play() {
System.out.println("狗正在play");
}
}
(4)
public class DogTest {
public static void main(String[] args) {
Dog dog=new Dog(3.0F);
dog.eat();
dog.feed();
dog.mokenoise();
dog.play();
dog.roam();
System.out.println(dog.size);
}
}