1、Java 編程思想（第四版）習題答案第二章練習 1： public class PrimitiveTest static int i;static char c;public static void main(String args) System.out.println("int = " + i);System.out.println("char = " + c);練習 2： public class HelloWorld public static void main(String args) System.out.println("Hel

2、lo World!");練習 3： public class ATNTest public static void main(String args) class ATypeName int i;double d;boolean b;void show() System.out.println(i);System.out.println(d);System.out.println(b);ATypeName a = new ATypeName();a.i = 3;a.d = 2.71828;a.b = false;a.show();練習 4： public class DataOnly

3、Test public static void main(String args) class DataOnly int i;double d;boolean b;void show() System.out.println(i);System.out.println(b);DataOnly data = new DataOnly();data.i = 3;data.d = 2.71828;data.b = false;data.show();練 5： public class DOTest2 public static void main(String args) class DataOnl

4、y int i;double d;boolean b;void show() System.out.println(i);System.out.println(d);System.out.println(b);DataOnly data = new DataOnly();data.i = 234;data.d = 2.1234545;data.b = true;data.show();練 6： public class StorageTest public static void main(String args) class StoreStuff int storage(String s)

5、return s.length() * 2;StoreStuff x = new StoreStuff();System.out.println(x.storage("hi");練 7：class StaticTest static int i = 47;class Incrementable static void increment() StaticTest.i+; public class ITest public static void main(String args) System.out.println("StaticTest.i= " +

6、 StaticTest.i);StaticTest st1 = new StaticTest();StaticTest st2 = new StaticTest();System.out.println("st1.i= " + st1.i);System.out.println("st2.i= " + st2.i);Incrementable sf = new Incrementable();sf.increment();System.out.println("After sf.increment() called: ");Syste

7、m.out.println("st1.i = " + st1.i);System.out.println("st2.i = " + st2.i);Incrementable.increment();System.out.println("After Incrementable.increment called: ");System.out.println("st1.i = " + st1.i);System.out.println("st2.i = " + st2.i);練習 8： class

8、StaticTest static int i = 47;class Incrementable static void increment() StaticTest.i+; public class OneStaticTest public static void main(String args) System.out.println("StaticTest.i= " + StaticTest.i);StaticTest st1 = new StaticTest();StaticTest st2 = new StaticTest();System.out.println

9、("st1.i= " + st1.i);System.out.println("st2.i= " + st2.i);Incrementable.increment();System.out.println("After Incrementable.increment() called: ");System.out.println("st1.i = " + st1.i);System.out.println("st2.i = " + st2.i);Incrementable.increment()

10、;System.out.println("After Incrementable.increment called: ");System.out.println("st1.i = " + st1.i);System.out.println("st2.i = " + st2.i);st1.i = 3;System.out.println("After st1.i = 3, ");System.out.println("st1.i = " + st1.i);System.out.println(&q

11、uot;st2.i = " + st2.i);System.out.println("Create another StaticTest, st3.");StaticTest st3 = new StaticTest();System.out.println("st3.i = " + st3.i);練習 9： public class AutoboxTest public static void main(String args) boolean b = false;char c = 'x'byte t = 8;short s

12、= 16;int i = 32;long l = 64;float f = 0.32f;double d = 0.64;Boolean B = b;System.out.println("boolean b = " + b);System.out.println("Boolean B = " + B);Character C = c;System.out.println("char c = " + c);System.out.println("Character C = " + C);Byte T = t;Syst

13、em.out.println("byte t = " + t);System.out.println("Byte T = " + T);Short S = s;System.out.println("short s = " + s);System.out.println("Short S = " + S);Integer I = i;System.out.println("int i = " + i);System.out.println("Integer I = " + I

14、);Long L = l;System.out.println("long l = " + l);System.out.println("Long L = " + L);Float F = f;System.out.println("float f = " + f);System.out.println("Float F = " + F);Double D = d;System.out.println("double d = " + d);System.out.println("Dou

15、ble D = " + D);練習 10 ： public class CommandArgTest public static void main(String args) intargs1=1,2,3;System.out.println("args0 = " + args10);System.out.println("args1 = " + args11);System.out.println("args2 = " + args12);練習 11：public class Rainbow public static v

16、oid main(String args) AllTheColorsOfTheRainbow atc = new AllTheColorsOfTheRainbow();System.out.println("atc.anIntegerRepresentingColors = " + atc.anIntegerRepresentingColors);atc.changeColor(7);atc.changeTheHueOfTheColor(77);System.out.println("After color change, atc.anIntegerReprese

17、ntingColors ="+atc.anIntegerRepresentingColors);System.out.println("atc.hue = " + atc.hue);class AllTheColorsOfTheRainbow int anIntegerRepresentingColors = 0;int hue = 0;void changeTheHueOfTheColor(int newHue) hue = newHue;int changeColor(int newColor) return anIntegerRepresentingColo

18、rs = newColor;練習 12 ： public class DocTest /* Entry poing to class & application.* param args array of string arguments* throws exceptions No exceptions thrown*/public static void main(String args) System.out.println("Hello, it's: ");System.out.println(new Date();練習 13-1： public cl

19、ass Documentation1 /* A field comment */public int i;/* A method comment */ public void f() 2： public class Documentation2 Date d = new Date();void showDate() System.out.println("Date = " + d);3： public class Documentation3 public static void main(String args) Date d = new Date();System.ou

20、t.println("d = " + d);練習 14 ： public class Documentation4 public int i = 2;private int j = 3;public static void main(String args) Date d = new Date();System.out.println("d = " + d);練習 15 ： public class HelloDocTest public static void main(String args) System.out.println("Hel

21、lo World!");練習 16 ：class Tree int height;Tree() System.out.println("Planting a seedling");height = 0;Tree(int initialHeight) height = initialHeight;System.out.println("Creating new tree that is " + height + " feet tall"); void info() System.out.println("Tree i

22、s " + height + " feet tall");void info(String s) System.out.println(s + ": Tree is " + height + " feet tall");public class Overloading public static void main(String args) for(int i = 0; i < 5; i+) Tree t = new Tree(i);();("overloading method&qu

23、ot;);/ Overloaded constructor:new Tree();第三章練習 1： public class PrintTest public static void main(String args) print("Hello, from short form."); P.rintln("Hello from greggordon form."); System.out.println("Hello from long form.");練習 2： class Tube float level;public class

24、 Assign public static void main(String args) Tube t1 = new Tube();Tube t2 = new Tube();t1.level = 0.9f;t2.level = 0.47f;+ t2.level);+ t2.level);+ t2.level);P.rintln("1: t1.level: " + t1.level + ", t2.level: " t1 = t2;P.rintln("2: t1.level: " + t1.level + ", t2.leve

25、l: " t1.level = 0.27f;P.rintln("3: t1.level: " + t1.level + ", t2.level: "練習 3： class Box float a;public class PassObject2 static void f(Box y) y.a = 2.71828f;public static void main(String args) Box x = new Box();x.a = 3.1416f;print("1: x.a = " + x.a);f(x);print(&

26、quot;2: x.a = " + x.a);練習 4： class VelocityCalculator static float velocity (float d, float t) if(t = 0) return 0f;else return d/t;public class VelocityTester public static void main(String args) float d = 565.3f;float t = 3.6f;System.out.println("Distance: " + d);System.out.println(&

27、quot;Time: " + t);float v = VelocityCalculator.velocity(d, t); System.out.println("Velocity: " + v);練習 5： class Dog String name;String says;void setName(String n) name = n;void setSays(String s) says = s;void showName() P.rintln(name);void speak() P.rintln(says);public class DogTest p

28、ublic static void main(String args) Dog spot = new Dog(); spot.setName("Spot");spot.setSays("Ruff!");Dog scruffy = new Dog(); scruffy.setName("Scruffy"); scruffy.setSays("Wurf!"); spot.showName();spot.speak(); scruffy.showName(); scruffy.speak();練習 6： class Dog String name;String says;void setName(String n) name = n;void setSays(String s) says = s;void showName() P.rintln(name);void speak() P.rintln(says);public class DogCompare public static void main(String args) Dog spot = new Dog();spo