JAVA編程思想課后習題答案

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(Hello 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 DataOnlyTest public static void main(String args) class DataOnly 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 = 3;data.d = 2.71828;data.b = false;data.show();練習5：public class DOTest2 public static void main(String args) class DataOnly 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();練習6：public class StorageTest public static void main(String args) class StoreStuff int storage(String s) return s.length() * 2;StoreStuff x = new StoreStuff();System.out.println(x.storage(hi);練習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= + 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: );System.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 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(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();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(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 = 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;System.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);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(Double D = + D);練習10：public class CommandArgTest public static void main(String args) System.out.println(args0 = + args0);System.out.println(args1 = + args1);System.out.println(args2 = + args2);練習11：public class Rainbow public static void 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.anIntegerRepresentingColors = + 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 anIntegerRepresentingColors = 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, its: );System.out.println(new Date();練習13-1：public class 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.out.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(Hello 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 is + 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);/ 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 Assign public static void main(String args) Tube t1 = new Tube();Tube t2 = new Tube();t1.level = 0.9f;t2.level = 0.47f;P.rintln(1: t1.level: + t1.level + , t2.level: + t2.level);t1 = t2;P.rintln(2: t1.level: + t1.level + , t2.level: + t2.level);t1.level = 0.27f; P.rintln(3: t1.level: + t1.level + , t2.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(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(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 public 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);p