java复习资料.doc

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 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.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 referenceCount； 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.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 Person 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 void 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(int 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 show() 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 CollegeStudent() 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=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.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(); 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 。classCrunchervoidcrunch(inti) System.out.print(“int”);voidcrunch(Strings) System.out.print(“String”);publicstaticvoidmain(Stringargs)Crunchercrun=newCruncher();charch=h;inti=12;crun.crunch(ch); System.out.print(“,”);crun.crunch(i);14阅读以下程序：importjava.io.*;publicclassAboutFilepublicstaticvoidmain(Stringargs)BufferedReaderb=newBufferedReader(newInputStreamReader(System.in);Strings;System.out.flush();try s=b.readLine();System.out.println(“Stringis:”+s); Catch(IOException e) System.out.println(e.getMessage(); 运行以上程序，若从键盘输入：java则输出结果为 。15写出以下程序的运行结果。publicclassTryCatchFinallystaticvoidProc(intsel)tryif(sel=0)System.out.println(noException);return;elseif(sel=1)inti=0;intj=4/i;catch(ArithmeticExceptione)System.out.println(Catch);catch(Exceptione)System.out.println(Willnotbeexecuted);finallySystem.out.println(finally);publicstaticvoidmain(Stringargs)Proc(0);Proc(1);输出结果为： 。15阅读以下程序，写出输出结果。classAnimal Animal()System.out.print(Animal);publicclassDogextendsAnimalDog() System.out.print(Dog);publicstaticvoidmain(Stringargs) Dogsnoppy=newDog();输出结果为： 。编程题1、编写一个类，要求该类实现一个接口，该接口有3个abstract方法： public abstract void f(int x); public abstract void g(int x, int y);public abstract double h