java复习资料

1、1、阅读以下程序，输出结果为 。class Q1public static void main（String args ）double d=1.23;Dec dec=new Dec( );dec.decrement(d);System.out.println(d);classs Decpublic void decrement(double decMe)decMe = decMe 0.1;2、以下程序段的输出结果为 。class Cruncher void crunch( int i ) System.out.println(“int version”); void crunch(String

2、 s) System.out.println(“String version”); public static void main(String args ) Crunchercrun=new Cruncher ( ); char ch=p; crun.crunch(ch); 3、阅读以下程序段:class Parentvoid printMe()System.out.println(“pt”);class Child extends Parentvoid printMe()System.out.print (“cd”);void printAll()super.printMe();this.

3、printMe();printMe();public class Test_thispublic static void main(String args )Child myC=new Child();myC.printAll();输出结果为 。4、已有Bird类的定义如下：package abcde;public class Bird protected static int referenceCount=0； public Bird（） referenceCount+； protected void fly（） static int getReCount（） return referenc

4、eCount； 有类Nightingale的定义如下，请写出它的输出结果 。package singers；class Nightingale extends abcde.Bird Nightingale( ) referenceCount+;public static void main( String args ) System.out.print(“Before:”+referenceCount); Nightingale florence=new Nightingale( ); System.out.println(“ After:”+referenceCount); florence

5、.fly( );5、以下程序段的输出结果为 。public class testpublic static void main(String args ) StringBuffer s = new StringBuffer("Hello"); s.append("there"); System.out.println(s); String pf = s.substring(0, s.length(); System.out.println(pf.equals("Hellothere"); 6、以下程序段的输出结果为 。class Pe

6、rson public Person() System.out.println("hi!"); public Person(String s) this(); System.out.println("I am "+s); public class Who extends Person public Who() this("I am Tony"); public Who(String s) super(s); System.out.println("How do you do?"); public static vo

7、id main(String args) Who w = new Who("Tom"); 7下面是一个类的定义。class _ / 定义名为MyClass的类 _ int var=666; static int getvar() return var; 8以下程序的输出结果为 。public class abc public static void main(String args ) SubSubClass x = new SubSubClass(10 , 20 , 30); x.show(); class SuperClass int a,b; SuperClass(i

8、nt aa , int bb) a=aa; b=bb; void show( ) System.out.println("a="+a+"nb="+b); class SubClass extends SuperClass int c; SubClass(int aa,int bb,int cc) super(aa,bb); c=cc; class SubSubClass extends SubClass int a; SubSubClass(int aa,int bb,int cc) super(aa,bb,cc);a=aa+bb+cc; void sh

9、ow() System.out.println("a="+a+"nb="+b+"nc="+c); 9以下程序的输出结果为 。class Person public Person() System.out.println("Person"); class Student extends Person publid Student() System.out.println("Student"); class CollegeStudent extends Student public CollegeS

10、tudent() System.out.println("CollegeStudent"); public class Test public static void main(String args) CollegeStudent cs=new CollegeStudent(); 10通过键盘输入10个整数，并按输入的倒序输出这10个整数。import java.io.*;public class Reverse public static void main(String args) int i,n=10; int a=new int10; for (i=0;i<

11、n;i+) try BufferedReader br=new BufferedReader( ); ai=Integer.parseInt( ); /输入一个整数 catch(IOException e); for(i=n-1;i>=0;i-) System.out.print(ai+" "); System.out.println(); 11以下程序的输出结果为 。public class EqualOrNot public static void main(String args) B b1=new B(5); B b2=new B(5); System.out

12、.println(b1=b2); System.out.println(b1.equals(b2); class B int x; B(int y) x=y; 12以下程序的输出结果为 。class Parent void printMe() System.out.println("parent"); class Child extends Parent void printMe() System.out.println("child"); void printAll() super.printMe(); this.printMe(); printMe(

13、); bpublic class Test_this public static void main(String args) Child myC=new Child(); myC.printAll(); 13以下程序的输出结果为                      。class  Crunchervoid  crunch( int

14、  i )     System.out.print(“int”);    void  crunch(String  s)  System.out.print(“String”); public  static  void main(String  args )Cruncher crun=new  Cruncher&#

15、160;( );char    ch=h;int    i=12;crun.crunch(ch); System.out.print(“,”);crun.crunch(i);      14阅读以下程序：import java.io.*;public class  AboutFile    public static void main(

16、String   args)       BufferedReader  b=new BufferedReader (new InputStreamReader(System.in);       String s;       System.out.flush();  

17、0;    try s=b.readLine();            System.out.println(“String is:”+s); Catch(IOException e) System.out.println(e.getMessage();     运行以上程序，若从键盘输入： java<回车>则输出结果为 。15写出以下程序的运行结果。public

18、 class TryCatchFinally    static void Proc( int sel )              try          if( sel=0 )System.out.println("

19、;no Exception ");             return;           else if( sel=1 )  int i=0;  int j=4/i;     

20、0;           catch( ArithmeticException e )   System.out.println("Catch ");          catch( Exception e )   System.out.p

21、rintln("Will not be executed");        finally  System.out.println("finally");        public static void main( String args )    Proc( 0 );      Proc( 1 );       输出结果为： 。15阅读以下程序，写出输出结果。class  Animal   Animal()     System.out.print ("Animal