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use java creat a class called dog_Thing in java 第5章,初始化和清理,練習題答案

public class Chap5Prac2 {

Chap5Prac2(){

s3 = "good bye";

}

String s1;

String s2 = "hello";

String s3;

public static void main(String[] args){

Chap5Prac2 t = new Chap5Prac2();

P.print("t.s1: "+t.s1);

P.print("t.s2: "+t.s2);

P.print("t.s3: "+t.s3);

}

}

public class Chap5Prac3DefaultConstructor{

Chap5Prac3DefaultConstructor(){

P.print("this is a default constructor");

}

public static void main(String[] args){

Chap5Prac3DefaultConstructor dc = new Chap5Prac3DefaultConstructor();

}

}

public class Chap5Prac4 {

Chap5Prac4(){

P.print("this is a default constructor");

}

Chap5Prac4(String s){

P.print("This is an overload constructor with input parameter: "+s);

}

public static void main(String[] args){

Chap5Prac4 t1 = new Chap5Prac4();

Chap5Prac4 t2 = new Chap5Prac4("Hello");

}

}

public class Chap5Prc5Dog {

void bark(){P.print("no parameter, quiet");}

void bark(byte b){P.print("byte parameter: miao");}

void bark(short s){P.print("short bark: wang");}

void bark(int i){P.print("int bark: wangwang");}

void bark(char c){P.print("char bark: chachacha");}

void bark(float f){P.print("float bark: fafafa");}

void bark(long l){P.print("long bark: lalala");}

void bark(double d){P.print("double bark: doudoudou");}

public static void main(String[] args){

byte b = 1;

short s = 2;

char c = 'c';

Chap5Prc5Dog dog = new Chap5Prc5Dog();

dog.bark();

dog.bark(b);

dog.bark(s);

dog.bark(1);

dog.bark(c);

dog.bark(1L);

dog.bark(1.0f);

dog.bark(1.0);

}

}

public class Chap5Prac6Dog1 {

void bark(int i, String s){

P.print("The first dog's name is " + s + ", it is "+i+" years old.");

}

void bark(String s, int i){

P.print("The second dog's name is "+ s+", it is "+i+" years old.");

}

public static void main(String[] args){

Chap5Prac6Dog1 dog = new Chap5Prac6Dog1();

dog.bark(1, "dog1");

dog.bark("dog2", 2);

}

}

public class Chap5Prac7Dog3 {

void bark(){

P.print("woof");

}

public static void main(String[] args){

Chap5Prac7Dog3 dog = new Chap5Prac7Dog3();

dog.bark();

}

}

public class Chap5Prac8 {

void method1(){

method2();

this.method2();

}

void method2(){

P.print("this is method 2");

}

public static void main(String[] args){

Chap5Prac8 test = new Chap5Prac8();

test.method1();

}

}

public class Chap5Prac9This {

Chap5Prac9This(int i){

P.print("This is the first constructor, the give number is: "+i);

}

Chap5Prac9This(String s){

this(7);

P.print("this is the second constructor, the string is: "+s);

}

public static void main(String[] args){

Chap5Prac9This ch = new Chap5Prac9This("sandy");

}

}

public class Chap5Prac10Finalize {

boolean logout = false;

Chap5Prac10Finalize(boolean logout){

logout = logout;

}

void checkOut(){

logout = false;

}

protected void finalize(){

if(logout)

P.print("error, logout");

}

public static void main(String[] args){

Chap5Prac10Finalize ch = new Chap5Prac10Finalize(true);

ch.checkOut();

new Chap5Prac10Finalize(true);

System.gc();

}

}