第3章JAVA选择题

class father {

public int addvalue(int a, int b){

int s =a+b;

return s;

}

}

class child extends father {

}

class Father {

}

class Child extends Father {

}

public class Main{

public static void main(String[]a){

Father f1=new Father();

System.out.println(f1 instanceof Father); //AA语句

System.out.println(f1 instanceof Child)；//BB语句

Father obj=new Child();

System.out.println(obj instanceof Father); //CC语句

System.out.println(obj instanceof Child)；//DD语句

Child c1=new Child();

System.out.println(c1 instanceof Father); //EE语句

System.out.printIn(c1 instanceof Child)； //FF语句

}

}

class Father{

int a = 100;

int b = 200；

public void print(){

System.out.println(a +""+ b);

}

}

class Child extends Father {

int b= 300;

int c = 400;

public void print(){

System.out.println(a+""+b+"" + c);

}

public void printExtend)(){

System.out.println(c);

}

}

public class Main{

public static void main(String[] a){

Father obj = new Child();

System.out.println(obj.a)；/ AA语句

System.out.println(obj.b);  / BB语句

obj.print();  / CC语句

obj.printExtend();  / DD语句

}

}

class A{

int v1= 10;

int v2= 10;

public A(){

}

public void m1(){

System.out.println("A m1");

}

public void m2(){

System.out. println("A m2");

}

}

class B extends A{

int v2=20;

int v3=20;

public B(){

}

public void m2(){

System.out. println("B m2");

}

public void m3(){

System.out.println("B m3");

}

}

public class Main {

public static void main(String[] args){

A a = new B();

a.m1();

a.m2();

System.out.println(a.v1);

System.out.println(a.v2)；

}

}

class A{

int i, j;

public void fun(){

i++;

j++;

}

}

class B extends A{

static int j;

public void func(){

int j= 2;

for(i=0;i<10;i++){

j+=3;

fun();

}

System.out.println(super.i + this. j);

System.out.printin(i + "" + j);

}

}

class Main{

public static void main(String[]args) throws Exception{

B b = new B();

b.func();

}

}

运行Main类，输出结果为

{

String color;

static String name=null;

static int count=0;

public Bird(String c){

count++;

color=c;

}

public String getString(){  //返回相关信息

return name+","+color+","+count;

}

}

public class Demo36{

public static void main(String args[])

{

Bird b1=new Bird("black");

Bird b2=new Bird("white");

Bird b3=new Bird("red");

Bird.name="大雁";

System.out.println(b1.getString());

System.out.println(b2.getString());

System.out.println(b3.getString());

}

}

class Test

{

private String name;

private int age;

public Test(){

System.out. printin("这是构造方法"）；

}

{System.out.println("这是普通初始化块”）；

}

static{

System.out.println("这是静态初始化块"）；

}

}

public class Demo

{

public static void main(String args[])

{

Test t=new Test();

}

}

public class Outer{

public String name;

public Outer(String n){

this.name=n;

}

public class Inner{

public String age;

}

}