JAVA编程思想第四版课后答案.pdf

Java 编程思想（第四版）习题答案 第二章 练习 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); 练习 2：public class HelloWorld public static void main(String args) System.out.println(“Hello World!“); 练习 3：public classATNTest public static void main(String args) classATypeName int i; double d; boolean b; void show() System.out.println(i); System.out.println(d); System.out.println(b); ATypeName a = newATypeName(); a.i = 3; a.d = 2.71828; a.b = false; a.show(); 练习 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(); 练习 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(); 练习 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“); 练习 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); 练习 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); 练习 9：public classAutoboxTest 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); 练习 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); 练习 11： public class Rainbow public static void main(String args) AllTheColorsOfTheRainbow atc = newAllTheColorsOfTheRainbow(); System.out.println(“atc.anIntegerRepresentingColors = “ + atc.anIntegerRepresentingColors); atc.changeColor(7); atc.changeTheHueOfTheColor(77); System.out.println(“Aftercolorchange,atc.anIntegerRepresentingColors=“+ atc.anIntegerRepresentingColors); System.out.println(“atc.hue = “ + atc.hue); classAllTheColorsOfTheRainbow int anIntegerRepresentingColors = 0; int hue = 0; void changeTheHueOfTheColor(int newHue) hue = newHue; int changeColor(int newColor) return anIntegerRepresentingColors = newColor; 练习 12：public class DocTest /* Entry poing to class System.out.println(new Date(); 练习 13-1：public class Documentation1 /* Afield comment */ public int i; /* Amethod 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); 练习 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); 练习 15：public class HelloDocTest public static void main(String args) System.out.println(“Hello World!“); 练习 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 练习 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.“); 练习 2：class Tube float level; public classAssign 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); 练习 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); 练习 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); 练习 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(); 练习 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