武科大java实验答案全.docx
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武科大java实验答案全.docx
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武科大java实验答案全
补充第一节的内容
publicclassMyJavaClass
{inta;
myjavaclass(inta){this.a=a;}
publicvoidmain()
{myjavaclassc1=newMyJavaClass();
System.out.printIn(c1.a);
}
System.out.printIn("程序结束。
");
}
1.上面的程序有几处错误?
请依次改正。
2.这个程序的源代码应该保存为什么名字的文件?
3.请写出编译和运行这个文件的完整命令,注意给出环境变量的设置(假设源文件保存在d:
\java目录)
4.如果在程序最前面加入下面语句:
packagePkg;
该程序又该如何编译和运行?
答案:
答案
(1):
修改以后的程序为(粗体为修改过的地方)
publicclassMyJavaClass
{inta;
MyJavaClass(inta){this.a=a;}
publicStaticvoidmain(Stringargs[])
{MyJavaClassc1=newMyJavaClass
(2)//此处的实际参数可为任意整数;
System.out.println(c1.a);
System.out.println("程序结束。
");
}
}
答案
(2)
publicclassMyJavaClass
{inta;
intmyjavaClass(inta){this.a=a;returna;}//注此处函数返回值可为任意类型
publicstaticvoidmain(Stringargs[])
{MyJavaClassc1=newMyJavaClass();
System.out.println(c1.a);System.out.println("程序结束。
");
}
}
2、答案:
这个程序的源代码应该保存为MyJavaClass.java。
3、答案
(1)
setclass=c:
\j2sdk\bin
setclasspath=d:
\java
编译:
javacd:
\java\MyJavaClass.java
运行:
javaMyJavaClass
答案
(2)
编译:
c:
\j2sdk\bin\javacd:
\java\MyJavaClass.java
setclasspath=d:
\java
运行:
javaMyJavaClass
4、答案:
如果在程序最前面加入语句:
packagepkg;
环境变量同3、设置
编译:
javac-d.d:
\java\MyJavaClass.java
运行:
javapkg.MyJavaClass
I实验1答案
1-(1-1):
importjava.io.*;
classRandomMonth
{publicstaticvoidmain(Stringargs[])
{Stringmonths[]={"January","February","March",
"April","May","June","July",
"Aguest","September","October",
"November","December"};
inti;
i=(int)(Math.random()*12);
System.out.println(months[i]);
}
}
1-(1-2):
importjava.io.*;
importjava.util.*;
classRandomMonth2
{publicstaticvoidmain(Stringargs[])
{Stringmonths[]={"January","February","March",
"April","May","June","July",
"Aguest","September","October",
"November","December"};
Randomr=newRandom();
inti;
i=Math.abs(r.nextInt())%12;
System.out.println(months[i]);
}
}
1-
(2)
importjava.util.*;
classRandomPx
{publicstaticvoidmain(Stringargs[])
{intnum[]=newint[20];
inti,j,temp;
Randomr=newRandom();
for(i=0;i<20;i++)
num[i]=r.nextInt();
for(i=0;i<19;i++)
for(j=0;j<19-i;j++)
{if(num[j]>num[j+1])
{temp=num[j];
num[j]=num[j+1];
num[j+1]=temp;
}
}
for(i=0;i<20;i++)
{if(i%5==0)System.out.print("\n\r");
System.out.print(num[i]+"");
}
}
}
II实验2答案
2-
(1)
publicclassstudentx{
privateStringno;
privateStringclassno
privateStringname;
privateStringsex;
privateintage;
studentx(){
no="1";
classno="1";
name="lucy";
sex="male";
age=0;
}
Stringgetno(){
returnno;
}
Stringgetclassno(){
returnclassno;
}
Stringgetname(){
returnname;
}
intgetage(){
returnage;
}
voidupdateage(intnewage){
this.age=newage;
}
publicStringtoString(){
return(name+"学生:
"+"性别"+sex+",年龄"+age+",学号为"+no+",班级为"+classno);
}
publicstaticvoidmain(String[]args){
studentxp=newstudentx();
p.updateage(25);
System.out.println(p.getage());
System.out.println(p);
}
};
2-
(2)
importjava.io.*;
importjava.util.*;
classSchool
{staticfloatscoreLine;
staticvoidsetscoreLine(floatscore)
{scoreLine=score;}
staticfloatgetscoreLine()
{returnscoreLine;}
}
classStudent
{Stringname,id;
floatcomScore,score;
floatgetcomScore()
{returncomScore;}
floatgetscore()
{returnscore;}
Student(Stringname,Stringid,floatcomScore,floatscore)
{this.name=name;
this.id=id;
Score=comScore;
this.score=score;
}
}
classEnroll
{staticbooleanisEnroll(Students)
{if(s.getcomScore()>=School.getscoreLine()||
(s.getscore()>96&&s.getcomScore()>=300))
returntrue;
elsereturnfalse;
}
publicstaticvoidmain(Stringargs[])
{Students[]=newStudent[3];
Stringinfo[]=newString[4];
inti,j;
StringmessInfo;
BufferedReaderin=newBufferedReader(newInputStreamReader(System.in));
StringTokenizerst;
School.setscoreLine(550);
for(i=0;i {try{messInfo=in.readLine(); st=newStringTokenizer(messInfo); for(j=0;j {info[j]=st.nextToken();} }catch(IOExceptionex){} s[i]=newStudent(info[0],info[1],Float.parseFloat(info[2]),Float.parseFloat(info[3])); } for(i=0;i if(isEnroll(s[i])) System.out.println(s[i].name+""+s[i].id+""+"被录取! "); else System.out.println(s[i].name+""+s[i].id+""+"没有录取! "); } } 2-(3)思考题: importjava.io.*; classComplex {doubleRealPart; doubleImageinPart; Complex(doublerp,doubleip) {RealPart=rp;ImageinPart=ip;} ComplexcomplexAdd(Complexa) {Complextemp; temp=newComplex(RealPart+a.RealPart,ImageinPart+a.ImageinPart); returntemp; } ComplexcomplexMinus(Complexa) {Complextemp; temp=newComplex(RealPart-a.RealPart,ImageinPart-a.ImageinPart); returntemp; } publicStringtoString() {if(ImageinPart<0) return(RealPart+"-"+Math.abs(ImageinPart)+"i"); else return(RealPart+"+"+ImageinPart*+"i"); } } classComplexApp {publicstaticvoidmain(Stringargs[]) {charoperator; try{ Complexc1=newComplex(1,2); Complexc2=newComplex(3,4); ComplexcomplexResult; operator=(char)System.in.read(); switch(operator) {case'+': complexResult=plexAdd(c2);break; case'-': complexResult=plexMinus(c2);break; } System.out.println(complexResult); } catch(IOExceptione) {System.out.println(e); } } } III实验3答案 3- (1) 1、classPerson { publicStringname; publicStringsex; intage; Person(Stringname,Stringsex,intage) {this.name=name; this.sex=sex; this.age=age; } } classStudentextendsPerson { publicStringsno; publicintclassno; publicvoidupdateAge(intage) {this.age=age; } Student(Stringname,Stringsex,intage,Stringsno,intclassno) {super(name,sex,age); this.sno=sno; this.classno=classno; } publicStringtoString() {System.out.println("name="+name+"sex="+sex+"age="+age+" sno="+sno+"classno"+classno+""); return"name="+name+"sex="+sex+"age="+age+"sno="+sno+"classno"+classno+""; } }; publicclassTestStudent { publicstaticvoidmain(String[]args) {Students1=newStudent("susan","女",20,"20031015123",2); s1.updateAge(21); s1.toString(); } } 3-(3) importjava.util.*; abstractclassEmployee {Stringname; longno; staticlongid=1000; abstractdoublegetPay(); Employee(Stringname){this.name=name;id=id+1;} }; classManagerextendsEmployee { doublepay=8000; doublegetPay(){return8000;} Manager(Stringname) {super(name); no=id; } publicStringtoString(){return"name: "+name+"no: "+no+"pay: 8000";} }; classSaleextendsEmployee {longsaleNum; doublegetPay(){returnsaleNum*0.4;} Sale(Stringname,longsaleNum) {super(name); no=id; this.saleNum=saleNum; } publicStringtoString() {return"name: "+name+"no: "+no+"pay: "+getPay();} } classTechextendsEmployee {longsalaryHours; doublegetPay() {returnsalaryHours*100;} Tech(Stringname,longsalaryHours) {super(name); no=id; this.salaryHours=salaryHours;} publicStringtoString() {return"name: "+name+"no: "+no+"pay: "+getPay();} }; classEmployApp { publicstaticvoidmain(Stringargs[]) { Vectorv=newVector(); Employeeem; doublenumPay=0; v.addElement(newSale("liping",10000)); v.addElement(newSale("susan",12000)); v.addElement(newTech("linda",40)); v.addElement(newTech("write",20)); v.addElement(newManager("gucci")); v.addElement(newManager("jessica")); Enumeratione=v.elements(); while(e.hasMoreElements()) { em=(Employee)e.nextElement(); numPay=numPay+em.getPay(); System.out.println(em); } System.out.println("总工资: "+numPay); } }; 实验4答案 4- (1) importjava.lang.*; importjava.io.*; classTestException { publicstaticvoidmain(String[]args) { try{ outofBound(); arraySize(); nullPointer(); } catch(NegativeArraySizeExceptione) {System.out.println(e.toString());} } staticvoidoutofBound() { try{ inti;inta[]; a=newint[10]; for(i=0;i<11;i++) {a[i]=i; System.out.println("a["+i+"]="+a[i]); } } catch(IndexOutOfBoundsExceptione) {System.out.println(e.toString());} } staticvoidnullPointer() { try{ Strings=null; System.out.println(s.length()); } catch(NullPointerExceptione) {System.out.println(e.toString());} } staticvoidarraySize()throwsNegativeArraySizeException { try{ inta[]; a=newint[-3]; } catch(NegativeArraySizeExceptione) {throwe;} } } 4- (2) classMyExceptionextendsException{ privateStringMsg; publicMyException(Stringmessage){ super(message); Msg=message; } publicvoidprintMsg(){ System.out.println(Msg); } } publicclassEX6_3{ voidGenerateMyException()throwsMyException{ thrownewMyException("此处发生异常信息"); } publicstaticvoidmain(Stringargs[]){ EX6_3obj=newEX6_3(); try{ obj.GenerateMyException(); } catch(MyExceptione){ e.printMsg(); } } } 4-(3)思考题 classNullParameterExceptionextendsException { NullParameterException(StringMessage) {super(Message); } }; classTestArea { publicstaticvoidmain(String[]args) { shapesh=null; intnum; num=args.length; try{ switch(num) {case1: sh=newZangle(Double.parseDouble(args[0]));break; Case2: sh=newLongangle(Double.parseDouble(args[0]),Double.parseDouble(args[1]));break; case3: sh=newTriangle(Double.parseDouble(args[0]),Double.parseDouble(args[1]),Double.parseDouble(args[2]));break; case0: thrownewNullParameterException("参数个数为零! "); } System.out.println(sh.area()); } catch(Exceptione) {System.out.println(e.toString());} } }; abstractclassshape { abstractdoublearea(); }; classTriangleext
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