java语言程序设计基础篇第十版第十三章练习答案.docx

java语言程序设计基础篇第十版第十三章练习答案.docx

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java语言程序设计基础篇第十版第十三章练习答案

01

publicclassExercise13_01{

publicstaticvoidmain（String[]args）{

TriangleNewtriangle=newTriangleNew（1,1.5,1）;

triangle.setColor（"yellow"）;

triangle.setFilled（true）;

System.out.println（triangle）;

System.out.println（"Theareais"+triangle.getArea（））;

System.out.println（"Theperimeteris"

+triangle.getPerimeter（））;

System.out.println（triangle）;

}

}

classTriangleNewextendsGeometricObject{

privatedoubleside1=1.0,side2=1.0,side3=1.0;

/**Constructor*/

publicTriangleNew（）{

}

/**Constructor*/

publicTriangleNew（doubleside1,doubleside2,doubleside3）{

this.side1=side1;

this.side2=side2;

this.side3=side3;

}

/**ImplementtheabstractmethodfindAreainGeometricObject*/

publicdoublegetArea（）{

doubles=（side1+side2+side3）/2;

returnMath.sqrt（s*（s-side1）*（s-side2）*（s-side3））;

}

/**ImplementtheabstractmethodfindCircumferencein

*GeometricObject

**/

publicdoublegetPerimeter（）{

returnside1+side2+side3;

}

@Override

publicStringtoString（）{

//Implementittoreturnthethreesides

return"TriangleNew:

side1="+side1+"side2="+side2+

"side3="+side3;

}

}

02

importjava.util.ArrayList;

publicclassExercise13_02{

publicstaticvoidmain（String[]args）{

ArrayListlist=newArrayList（）;

list.add（14）;

list.add（24）;

list.add（4）;

list.add（42）;

list.add（5）;

shuffle（list）;

for（inti=0;i

System.out.print（list.get（i）+""）;

}

publicstaticvoidshuffle（ArrayListlist）{

for（inti=0;i

intindex=（int）（Math.random（）*list.size（））;

Numbertemp=list.get（i）;

list.set（i,list.get（index））;

list.set（index,temp）;

}

}

}

03

importjava.util.ArrayList;

publicclassExercise13_03{

publicstaticvoidmain（String[]args）{

ArrayListlist=newArrayList（）;

list.add（14）;

list.add（24）;

list.add（4）;

list.add（42）;

list.add（5）;

sort（list）;

for（inti=0;i

System.out.print（list.get（i）+""）;

}

publicstaticvoidsort（ArrayListlist）{

for（inti=0;i

//Findtheminimuminthelist[i..list.length-1]

NumbercurrentMin=list.get（i）;

intcurrentMinIndex=i;

for（intj=i+1;j

if（currentMin.doubleValue（）>list.get（j）.doubleValue（））{

currentMin=list.get（j）;

currentMinIndex=j;

}

}

//Swaplist.get（i）withlist.get（currentMinIndex）ifnecessary;

if（currentMinIndex!

=i）{

list.set（currentMinIndex,list.get（i））;

list.set（i,currentMin）;

}

}

}

}

04

importjava.util.*;

publicclassExercise13_04{

staticMyCalendarcalendar=newMyCalendar（）;

publicstaticvoidmain（String[]args）{

intmonth=calendar.get（MyCalendar.MONTH）+1;

intyear=calendar.get（MyCalendar.YEAR）;

if（args.length>2）

System.out.println（"UsagejavaExercise13_04monthyear"）;

elseif（args.length==2）{

//useuser-definedmonthandyear

year=Integer.parseInt（args[1]）;

month=Integer.parseInt（args[0]）;

calendar.set（Calendar.YEAR,year）;

calendar.set（Calendar.MONTH,month-1）;

}

elseif（args.length==1）{

//useuser-definedmonthforthecurrentyear

month=Integer.parseInt（args[0]）;

calendar.set（Calendar.MONTH,month-1）;

}

//setdatetothefirstdayinamonth

calendar.set（Calendar.DATE,1）;

//printcalendarforthemonth

printMonth（year,month）;

}

staticvoidprintMonth（intyear,intmonth）{

//getstartdayoftheweekforthefirstdateinthemonth

intstartDay=getStartDay（）;

//getnumberofdaysinthemonth

intnumOfDaysInMonth=calendar.daysInMonth（）;

//printheadings

printMonthTitle（year,month）;

//printbody

printMonthBody（startDay,numOfDaysInMonth）;

}

staticintgetStartDay（）{

returncalendar.get（Calendar.DAY_OF_WEEK）;

}

staticvoidprintMonthBody（intstartDay,intnumOfDaysInMonth）{

//printpaddingspacebeforethefirstdayofthemonth

inti=0;

for（i=0;i

System.out.print（""）;

for（i=1;i<=numOfDaysInMonth;i++）{

if（i<10）

System.out.print（""+i）;

else

System.out.print（""+i）;

if（（i+startDay-1）%7==0）

System.out.println（）;

}

System.out.println（""）;

}

staticvoidprintMonthTitle（intyear,intmonth）{

System.out.println（""+calendar.getMonthName（）+","+year）;

System.out.println（"-----------------------------"）;

System.out.println（"SunMonTueWedThuFriSat"）;

}

}

05

publicclassExercise13_05{

//Mainmethod

publicstaticvoidmain（String[]args）{

//Createtwocomparablecircles

Circle1circle1=newCircle1（5）;

Circle1circle2=newCircle1（4）;

//Displaythemaxcircle

Circle1circle=（Circle1）GeometricObject1.max（circle1,circle2）;

System.out.println（"Themaxcircle'sradiusis"+circle.getRadius（））;

System.out.println（circle）;

}

}

abstractclassGeometricObject1implementsComparable{

protectedStringcolor;

protecteddoubleweight;

//Defaultconstruct

protectedGeometricObject1（）{

color="white";

weight=1.0;

}

//Constructageometricobject

protectedGeometricObject1（Stringcolor,doubleweight）{

this.color=color;

this.weight=weight;

}

//Gettermethodforcolor

publicStringgetColor（）{

returncolor;

}

//Settermethodforcolor

publicvoidsetColor（Stringcolor）{

this.color=color;

}

//Gettermethodforweight

publicdoublegetWeight（）{

returnweight;

}

//Settermethodforweight

publicvoidsetWeight（doubleweight）{

this.weight=weight;

}

//Abstractmethod

publicabstractdoublegetArea（）;

//Abstractmethod

publicabstractdoublegetPerimeter（）;

publicintcompareTo（GeometricObject1o）{

if（getArea（）

return-1;

elseif（getArea（）==o.getArea（））

return0;

else

return1;

}

publicstaticGeometricObject1max（GeometricObject1o1,GeometricObject1o2）{

if（pareTo（o2）>0）

returno1;

else

returno2;

}

}

//Circle.java:

ThecircleclassthatextendsGeometricObject

classCircle1extendsGeometricObject1{

protecteddoubleradius;

//Defaultconstructor

publicCircle1（）{

this（1.0,"white",1.0）;

}

//Constructcirclewithspecifiedradius

publicCircle1（doubleradius）{

super（"white",1.0）;

this.radius=radius;

}

//Constructacirclewithspecifiedradius,weight,andcolor

publicCircle1（doubleradius,Stringcolor,doubleweight）{

super（color,weight）;

this.radius=radius;

}

//Gettermethodforradius

publicdoublegetRadius（）{

returnradius;

}

//Settermethodforradius

publicvoidsetRadius（doubleradius）{

this.radius=radius;

}

//ImplementthefindAreamethoddefinedinGeometricObject

publicdoublegetArea（）{

returnradius*radius*Math.PI;

}

//ImplementthefindPerimetermethoddefinedinGeometricObject

publicdoublegetPerimeter（）{

return2*radius*Math.PI;

}

//Overridetheequals（）methoddefinedintheObjectclass

publicbooleanequals（Circle1circle）{

returnthis.radius==circle.getRadius（）;

}

@Override

publicStringtoString（）{

return"[Circle]radius="+radius;

}

@Override

publicintcompareTo（GeometricObject1o）{

if（getRadius（）>（（Circle1）o）.getRadius（））

return1;

elseif（getRadius（）<（（Circle1）o）.getRadius（））

return-1;

else

return0;

}

}

06

publicclassExercise13_06{

//Mainmethod

publicstaticvoidmain（String[]args）{

//Createtwocomarablerectangles

ComparableCirclecircle1=newComparableCircle（5）;

ComparableCirclecircle2=newComparableCircle（15）;

//Displaythemaxrect

ComparableCirclecircle3=（ComparableCircle）Max.max（circle1,circle2）;

System.out.println（"Themaxcircle'sradiusis"+circle3.getRadius（））;

System.out.println（circle3）;

}

}

classComparableCircleextendsCircleimplementsComparable{

/**ConstructaComparableRectanglewithspecifiedproperties*/

publicComparableCircle（doubleradius）{

super（radius）;

}

@Override

publicintcompareTo（ComparableCircleo）{

if（getRadius（）>o.getRadius（））

return1;

elseif（getRadius（）

return-1;

else

return0;

}

}

//Max.java:

Findamaximumobject

classMax{

/**Returnthemaximumoftwoobjects*/

publicstaticComparableCirclemax

（ComparableCircleo1,ComparableCircleo2）{

if（pareTo（o2）>0）

returno1;

else

returno2;

}

}

07

publicclassExercise13_07{

publicstaticvoidmain（String[]args）{

GeometricObject[]objects={newSquare

（2）,newCircle（5）,newSquare（5）,newRectangle（3,4）,newSquare（4.5）};

for（inti=0;i

System.out.println（"Areais"+objects[i].getArea（））;

if（objects[i]instanceofColorable）

（（Colorable）objects[i]）.howToColor（）;

}

}

}

interfaceColorable{

voidhowToColor（）;

}

classSquareextendsGeometricObjectimplementsColorable{

privatedoubleside;

publicSquare（doubleside）{

this.side=side;

}

@Override

publicvoidhowToColor（）{

System.out.println（"Colorallfoursides"）;

}

@Override

publicdoublegetArea（）{

returnside*side;

}

@Override

publicdoublegetPerimeter（）{

return4*side;

}

}

08

importjava.util.ArrayList;

publicclassExercise13_08{

publicstaticvoidmain（String[]args）{

MyStack1stack=newMyStack1（）;

stack.push（"S1"）;

stack.push（"S2"）;

stack.push（"S"）;

MyStack1stack2=（MyStack1）（stack.clone（））;

stack2.push（"S1"）;

stack2.push（"S2"）;

stack2.push（"S"）;

System.out.println（stack.getSize（））;

System.out.println（stack2.getSize（））;

}

}

classMyStack1implementsCloneable{

privateArrayList