（7-1）以下程序运行结果是()。
class FatherX{
public Integer getX() {
return new Integer(10);
}
}
class Son extends FatherX{
public Double getX() {
return new Double(20);
}
}
public class Demo12 {
public static void main(String[] args) {
FatherX f=new FatherX();
Son s=new Son();
System.out.println(f.getX()+s.getX());
}
}
class FatherX{
public Integer getX() {
return new Integer(10);
}
}
class Son extends FatherX{
public Double getX() {
return new Double(20);
}
}
public class Demo12 {
public static void main(String[] args) {
FatherX f=new FatherX();
Son s=new Son();
System.out.println(f.getX()+s.getX());
}
}
举一反三
- （7-1）请阅读程序，并写出程序运行结果。 class X{ int getX() { return 5; } } class Y extends X{ int getX() { return 6; } } class T extends X{ int getX() { return 7; } } public class Demo10 { public static void main(String[] args) { X x=new X(); Y y=new Y(); X t=new T(); int sum=x.getX()+y.getX()+t.getX(); System.out.println(sum); } }
- （7-12）请阅读程序，写出程序运行结果。 class A{ static String name="tom"; static int getX() { return 2; } int getY() { return 3; } } class B extends A{ static String name="Tuny"; static int getX() { return 4; } int getY() { return 5; } } class C extends A{ static String name="Tuny"; static int getX() { return 4; } int getY() { return 5; } } interface D{ int getY(); } class E implements D{ public int getY() { return 6; } } public class Demo{ public static void main(String[] args) { A a=new A(); A b=new B(); A c=new C(); D d=new E(); int sum=a.name.length()+b.getX()+c.getY()+d.getY(); System.out.println(sum); } }
- （7-1）以下程序的运行结果是（ ）。 class A{ A(){ System.out.print(10); } } public class Demo extends A { public static void main(String[] args) { new A(); new Demo(); } }
- 下列程序运行结果是( ) public class Demo { public static void main(String[] args) { Demo demo = new Demo(); demo.show(new Car() { public void run() { System.out.println("demo run"); } }); } public void show(Car c) { c.run(); } }abstract class Car { public void run() { System.out.println("car run..."); } }
- 下列程序运行结果是 public class Demo { public static void main(String[] args) { Object obj=new Father(){ public void show(){ System.out.println("helloworld"); } }; obj.show(); } } class Father{ public void show(){ System.out.println("hello father"); } }