java语言程序设计基础篇第十版第十三章练习答案讲课讲稿.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讲课讲稿
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;iSystem.out.print（list.get（i）+""）;
}
publicstaticvoidshuffle（ArrayListlist）{
for（inti=0;iintindex=（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;iSystem.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;jif（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;iSystem.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;iSystem.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
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