《Java程序设计案例教程》实验指导实验1-17Java开发环境的搭建-集合框架类及其应用

《Java程序设计案例教程(微课版)》--实验指导(附答案版)二、实验内容(需要提交源程序的题目可以粘贴代码，也可以截图)略2、编写程序，在屏幕上显示：“我爱Java!”publicclassMain{publicstaticvoidmain(String[]args){System.out.println("我爱Java！");}}publicclassMain{publicstaticvoidmain(String[]args){System.out.println("*");System.out.println("***");System.out.println("*****");System.out.println("********");System.out.println("**********");}}publicclassPerson{voidspeakHello(){stemoutprintSystem.out.println("nicetomeetyou");}}classXiti{publicstaticvoidmain(Stringargs[]){2Personzhang=newPerson();zhang.speakHello();}}(a)上述源文件的名字是什么？(b)编译上述源文件将生成几个字节码文件？这些字节码文件的名字都是什么？(a)Xiti.java与public修饰的类一致，与主类(包含main方法的类)一致。符及表达式求值3ngargsintx='A';b}}ngargsoutprintxx}}ngargs}}publicpublicclassMain{publicstaticvoidmain(String[]args){oubleadoublec;doublepab+c)/2;doublesMathsqrtppap-b)*(p-c));4}}请求出方程publicpublicclassMain{publicstaticvoidmain(String[]args){xbMathsqrtd*a);xbMathsqrtd*a);stemoutprintlnxxnxx}}5publicclassMain{publicstaticvoidmain(String[]args){nerSysteminprintlnaatbb}}publicclassMain{publicstaticvoidmain(String[]args){nerSystemin}}publicclassMain{publicstaticvoidmain(String[]args){nnerSystemin6extDoubleextDoubleextDoubledoublepab+c)/2;doublesMathsqrtppap-b)*(p-c));}}publicclassMain{icstaticvoidmainStringargsnerSysteminrintlna}}7publicclassMain{icstaticvoidmainStringargsnerSystemin}tprintlnaabb}}publicclassMain{icstaticvoidmainStringargsnerSysteminprintlnemoutprintlntemoutprintln}}}8}}并进一步判断其是等边三角形，还是等腰三角形，还importimportjava.util.Scanner;publicclassMain{icstaticvoidmainStringargsnerSysteminoubleoubleoubleoutprintlnoutprintln}temoutprintln}outprintln}}}publicclassMain{icstaticvoidmainStringargsnerSysteminoubleoutprintln9tlntlnntln}}}||x<0)publicclassMain{icstaticvoidmainStringargsnerSysteminy=-1;}lnyy}}publicclassMain{icstaticvoidmainStringargsScannersc=newScanner(System.in);SystemSystem.out.println("请输三个数:");}//intmax=Math.max(a,Math.max(b,c));//System.out.println(max);}}publicclassMain{icstaticvoidmainStringargsnerSystemin}}}emoutprintlnaanbbncc}}publicclassMain{icstaticvoidmainStringargsnerSysteminntlnntlnntlnntlnntlnntlnntlndefault:println}}}publicclassMain{publicstaticvoidmain(Stringargs[]){nnerSysteminrintlnswitch(n){tlntlntlnntlndefault:outprintln}}}1111、实现计算器功能(只包含基本的+、-、*、/即可)。publicclassMain{publicstaticvoidmain(String[]args){nnerSysteminextDoubletextDoubleswitchop{case"+":case"-":case"*":case"/":default:}}}publicpublicclassMainpublicstaticvoidmain(String[]args){while(i<101){}dodo{}}publicpublicclassMain{publicstaticvoidmain(String[]args){for(inti=1;i<6;i++){}}}publicpublicclassMain{publicstaticvoidmain(String[]args){for(inti=1;i<19;i++){}}}学生成绩，计算出平均成绩。当输入分数为负数时，表示输入结束。publicclassMain{publicstaticvoidmain(String[]args){nnerSysteminwhile(true){nextDoubleifif(a>=0){tln}}tprintlnp}}、猜数游戏：让用户猜数，一直到猜对为止。在最后提示是猜了几次猜对的。publicclassMain{publicstaticvoidmain(String[]args){nnerSysteminintaintMathrandomwhile(true){if(a>b){ntlnfabntlnprintln}}emoutprintlnt}}publicpublicclassMain{publicstaticvoidmain(String[]args){for(inti=3;i<=100;i+=3){}}}publicpublicclassMain{publicstaticvoidmain(String[]args){for(charc='a';c<='z';c++){}}}publicclassMain{publicstaticvoidmain(String[]args){nnerSysteminntlnfor(inti=1;i<x;i++){if(x%i==0){}}}if(sum==x){ntlnprintln}}}publicpublicclassMainpublicstaticvoidmain(String[]args){for(inti=1;i<101;i++){if(isPerfectNumber(i)){tlni}}}publicstaticbooleanisPerfectNumber(inta){for(inti=1;i<a;i++){if(a%i==0){}}if(sum==a){}}}5.判断一个数是否质数。rpublicclassMain{publicstaticvoidmain(String[]args){cnewScannerSystemintprintlnif(a>2){for(inti=2;i*i<=a;i++){ifif(a%i==0){f=false;}}f=false;}if(f){tprintlnutprintln}}}6.查找1-100所有的质数(素数)。publicpublicclassMain{publicstaticvoidmain(String[]args){for(inti=1;i<101;i++){if(isPrimeNumber(i)){tlni}}}publicstaticbooleanisPrimeNumber(inta){if(a<2){}for(inti=2;i*i<=a;i++){if(a%i==0){}}}}7.查找水仙花数的个数。publicclassMain{publicstaticvoidmain(String[]args){for(inti=100;i<1000;i++)beritlncont}publicpublicstaticbooleanisNarcissisticNumber(inti){if(i==Math.pow(a,3)+Math.pow(b,3)+Math.pow(c,3)){}}}8.查找用户输入的十个数中的最大值。publicclassMain{publicstaticvoidmain(String[]args){cnewScannerSysteminfor(inti=0;i<10;i++){}Arrayssortarr);Systemoutprintlnarrrintlnmaxarr}publicstaticintmax(int[]arr){for(inti=1;i<arr.length;i++){if(max<arr[i]){}}}}9.输出九九乘法表。源程序:classclassMain{publicstaticvoidmain(String[]args){for(inti=1;i<10;i++){for(intj=1;j<=i;j++){Systemoutprintji"="+i*j+"\t");}ntln}}}}publicclassMain{publicstaticvoidmain(String[]args){for(inti=-3;i<4;i++){for(inta=1;a<=Math.abs(i);a++){rint}for(intb=1;b<=7-2*Math.abs(i);b++){rint}ntln}}}publicclassMain{publicstaticvoidmain(String[]args){while(sum<=100){}tlni}}importimportjava.util.Scanner;publicclass绝对值{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);System.out.println("请输入要找绝对值的数");intn=in.nextInt();System.out.println(n+"的绝对值是"+jueduizhi(n));}staticdoublejueduizhi(doublex){doublejueduizhi;jueduizhi=Math.abs(x);returnjueduizhi;}}importjava.util.Scanner;publicclass判断平年闰年{publicstaticvoidmain(String[]args){Scannerin=newScanner(System.in);intn=in.nextInt();if(nian(n)){System.out.println(n+"是闰年");}else{System.out.println(n+"不是闰年");}}staticbooleannian(inty){if((y%4==0&&y%100!=0)||(y%400==0)){returntrue;}else{returnfalse;}}}importjava.util.Scanner;publicclass长方形面积体积{publicstaticvoidmain(String[]args){DOdoubledoublea,b,c,mianji,tiji;Scannerin=newScanner(System.in);System.out.println("请输入长方形的长宽高");a=in.nextDouble();b=in.nextDouble();c=in.nextDouble();mianji=mianji(a,b);tiji=tiji(a,b,c);System.out.println("长方形面积是"+mianji(a,b)+"体积是"+tiji(a,b,c));}staticdoublemianji(doublex,doubley){doublemianji,tiji;mianji=x*y;returnmianji;}staticdoubletiji(doublex,doubley,doublez){doublemianji,tiji;tiji=x*y*z;returntiji;}}importjava.util.Scanner;publicclass判断水仙花数{publicstaticvoidmain(String[]args){Scannerin=newScanner(System.in);intn=in.nextInt();if(shuixianhua(n)){System.out.println(n+"是水仙花数");}else{System.out.println(n+"不是水仙花数");}}staticbooleanshuixianhua(inta){intb,c,d;if((a+"").length()==3){b=a/1000;c=a/10%10;d=a%10;if(b*b*b+c*c*c+d*d*d==a){returntrue;}else{returnfalse;}}else{returnfalse;}}}}importjava.util.Scanner;publicclass返回月份天数{publicstaticvoidmain(String[]args){Scannerin=newScanner(System.in);inta,b,c;System.out.println("请输入年份和月份");a=in.nextInt();b=in.nextInt();c=nianfen(a,b);System.out.println(a+"年"+b+"月有"+c+"天");}staticintnianfen(intx,inty){switch(y){casecasecasecasecasecasecase1:3:5:7:8:10:12:return31;//对于2月份需要判断是否为闰年case2:if(x%4==0&&x%100!=0){return29;}elseif(x%400==0){return29;}else{return28;}case4:case6:case9:case11:return30;default:return0;}}}importjava.util.Scanner;publicclass方法嵌套求体积{publicpublicstaticvoidmain(String[]args){DOdoublea,b,c;Scannerin=newScanner(System.in);System.out.println("请输入长方形的长宽高(");a=in.nextDouble();b=in.nextDouble();c=in.nextDouble();System.out.println("长方体积是"+tiji(a,b,c));}staticdoublemianji(doublex,doubley){doublemianji;mianji=x*y;returnmianji;}staticdoubletiji(doublex,doubley,doublez){doubletiji;tiji=mianji(x,y)*z;returntiji;}}importjava.util.Scanner;publicclass递归求阶乘{publicstaticvoidmain(String[]args){Scannerin=newScanner(System.in);inta=in.nextInt();System.out.println(a+"的阶乘是"+jiecheng(a));}staticintjiecheng(intn){if(n==1){returnn;}else{returnjiecheng(n-1)*n;}}}iimportjava.util.Scanner;publicclass求班级平均分{staticdoubleqiuhe(double[]b){doublesum=0;for(inti=0;i<b.length;i++)sum=sum+b[i];returnsum;}staticdoublepingjunzhi(double[]b){doublemean=0;mean=qiuhe(b)/b.length;returnmean;}publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);intb=0;System.out.println("请输入班级人数");b=in.nextInt();double[]a=newdouble[b];doublen=0;for(inti=0;i<a.length;i++){n=in.nextDouble();a[i]=n;}System.out.println("班级平均分为"+pingjunzhi(a));}}publicclass求出现次数{publicstaticvoidmain(String[]args){DOintx,b,d=0;Scannerin=newScanner(System.in);System.out.println("请输入要查找的元素");b=in.nextInt();int[]a={1,3,5,9,4,5,9,6,5,1,3,4,7,9,5,6,4,1};for(inti=0;i<a.length;i++){if(a[i]==b){d++;}}System.out.println(b+"出现了"+d+"次");}}}publicclass数组求斐波那契且数列{publicstaticvoidmain(String[]args){int[]a=newint[20];a[0]=1;a[1]=1;for(inti=2;i<a.length;i++){a[i]=a[i-1]+a[i-2];}for(inti=0;i<a.length;i++){System.out.print(a[i]+"");}}}。importjava.util.Scanner;publicclass倒序数组{staticvoidfangfa(doublea[]){for(inti=a.length-1,j=0;i>=0;i--,j++){doubleb;b=a[a.length-i-1];a[a.length-i-1]=a[j];//用中间数交换一下位置就可以了a[j]=b;}for(inti=0;i<a.length;i++){System.out.print(a[i]+"");}}publicstaticvoidmain(String[]args){Scannerin=newScanner(System.in);doublen=0;intc=0;System.out.println("请输入你要倒序的数组的元素的个数");//不加这个就会倒序的时候出现很多零.零(数组初始化0.0)c=in.nextInt();double[]b=newdouble[c];for(inti=0;i<b.length;i++){n=in.nextDouble();b[i]=n;}fangfa(b);}}5、在数组中查找x是否存在，如果存在将其删除，如果不存在做出提示。importimportjava.util.Scanner;publicclass数组删除{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);int[]a={3,2,5,5,1,5,5,5,9};System.out.print("之前的数组：");for(intx:a){System.out.print(x+"");}System.out.println();System.out.println("请输入要删除的数字");intshanchush=in.nextInt();intb=a.length;intd=0,c=0,e=0;;for(inti=0;i<b;i++){if(a[i]==shanchush){e++;}}if(e>0){for(intj=0;j<e;j++){for(inti=0;i<a.length;i++){if(a[i]==shanchush){d=i;c++;break;}}for(inti=d;i<a.length-c;i++){a[i]=a[i+1];}a[a.length-1]=0;b--;//删除一个数后，数组实际长度减一}System.out.print("之后的数组：");for(inti=0;i<b;i++){System.out.print(a[i]+"");}}else{System.out.println("没有要删除的数字");}}}importimportjava.util.Scanner;publicpublicclass数组插入元素{publicstaticvoidmain(String[]args){DOint[]a={1,2,3,4,5,7,8,9};int[]b=newint[a.length+1];Scannerin=newScanner(System.in);System.out.println("请输入要插入的数");intc=in.nextInt();dijia:for(inti=0;i<a.length;i++){if(c<=a[i]){b[i]=c;for(intj=i;j<b.length-1;j++){b[j+1]=a[j];}breakdijia;}else{b[i]=a[i];}}if(b[b.length-1]<c){b[b.length-1]=c;}for(inti=0;i<b.length;i++){System.out.println(b[i]+"");}}}77、借助任意一种排序算法对某班的Java成绩进行升序排序。importjava.util.Scanner;publicclass借用任何一种算法对数组排序{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);intn=0;System.out.println("请输入要排序的数组个数");n=in.nextInt();int[]a=newint[n];for(inti=0;i<a.length;i++){n=in.nextInt();a[i]=n;}for(inti=1;i<a.length;i++){for(intj=0;j<a.length-i;j++){if(a[j]>a[j+1]){intb;b=a[j];a[j]=a[j+1];a[j+1]=b;}}}}for(inti=0;i<a.length;i++){System.out.println(a[i]+"");}}}测分析平台：分析自己家乡2020年空气质量AQI的平均值。源程序：publicclass济南空气质量{staticdoubleqiuhe(double[]b){//数组值的合doublesum=0;for(inti=0;i<b.length;i++)sum=sum+b[i];returnsum;}staticdoublepingjunzhi(double[]b){doublemean=0;mean=qiuhe(b)/b.length;returnmean;}//总体方差staticdoublefangcha(double[]b){doublefangcha=0;for(inti=0;i<b.length;i++){fangcha=fangcha+(Math.pow((b[i]-pingjunzhi(b)),2));}fangcha=fangcha/(b.length-1);returnfangcha;}publicstaticvoidmain(String[]args){DOint[]e={2019,2020,2021};double[]a={132,125,92,92,102,143,120,75,104,87,96,114};//2019double[]b={141,77,78,85,101,123,96,81,92,79,89,116};//2020double[]c={122,75,135,90,114,122,79,99,73,73,82,82};//2021double[][]d={a,b,c};for(inti=0;i<d.length;i++){if(pingjunzhi(d[i])<=50){System.out.println(e[i]+"年空气质量是优");SystemSystem.out.println(e[i]+"年方差是"+fangcha(d[i]));System.out.println(e[i]+"年平均均数是"+pingjunzhi(d[i]));}elseif(pingjunzhi(d[i])<=100){System.out.println(e[i]+"年空气质量是良");System.out.println(e[i]+"年方差是"+fangcha(d[i]));System.out.println(e[i]+"年平均均数是"+pingjunzhi(d[i]));}elseif(pingjunzhi(d[i])<=150){System.out.println(e[i]+"年空气质量是轻度污染");System.out.println(e[i]+"年方差是"+fangcha(d[i]));System.out.println(e[i]+"年平均均数是"+pingjunzhi(d[i]));}elseif(pingjunzhi(d[i])<=200){System.out.println(e[i]+"年空气质量是中度污染");System.out.println(e[i]+"年方差是"+fangcha(d[i]));System.out.println(e[i]+"年平均均数是"+pingjunzhi(d[i]));}elseif(pingjunzhi(d[i])<=300){System.out.println(e[i]+"年空气质量是重度污染");System.out.println(e[i]+"年方差是"+fangcha(d[i]));System.out.println(e[i]+"年平均均数是"+pingjunzhi(d[i]));}else{System.out.println(e[i]+"年空气质量是严重污染");System.out.println(e[i]+"年方差是"+fangcha(d[i]));System.out.println(e[i]+"年平均均数是"+pingjunzhi(d[i]));}}}}publicclass方差{staticdoubleqiuhe(double[]b){//数组值的合doublesum=0;for(inti=0;i<b.length;i++)sum=sum+b[i];returnsum;}staticdoublepingjunzhi(double[]b){//平均值doublemean=0;mean=qiuhe(b)/b.length;returnmean;}////总体方差staticdoublefangcha(double[]b){doublefangcha=0;for(inti=0;i<b.length;i++){fangcha=fangcha+(Math.pow((b[i]-pingjunzhi(b)),2));}fangcha=fangcha/b.length;returnfangcha;}//总体标准差staticdoublebiaozhuncha(double[]b){doublebiaozhuncha;biaozhuncha=Math.sqrt(fangcha(b));returnbiaozhuncha;}//样本方差staticdoubleyangbenfangcha(double[]b){doubleyangbenfangcha=0;for(inti=0;i<b.length;i++){yangbenfangcha=yangbenfangcha+(Math.pow((b[i]-pingjunzhi(b)),2));}yangbenfangcha=yangbenfangcha/(b.length-1);returnyangbenfangcha;}//样本标准差staticdoubleyangbenbiaozhuncha(double[]data){doubleyangbenfangcha;yangbenfangcha=Math.sqrt(yangbenfangcha(data));returnyangbenfangcha;}publicstaticvoidmain(String[]args){Scannerin=newScanner(System.in);double[]b=newdouble[100];doublen;for(inti=0;i<100;i++){n=in.nextDouble();if(n!=-1){b[i]=n;}else{break;}}}}importimportjava.util.Scanner;publicclass查找x是否存在{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);int[]a={3,2,5,5,1,5,5,5,9};intcount=0,xiabiao=0;intchazhaoshu=in.nextInt();for(inti=0;i<a.length;i++){if(a[i]==chazhaoshu){count=1;xiabiao=i;break;}}if(count==0){System.out.println("没有找到相应元素");}else{System.out.println("找到相应元素，它的下标是"+xiabiao);}}}22、在一数组中查找值为x的元素，找到后将其删除。importjava.util.Scanner;publicclass数组删除{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);int[]a={3,2,5,5,1,5,5,5,9};System.out.print("之前的数组：");for(intx:a){System.out.print(x+"");}SystemSystem.out.println();System.out.println("请输入要删除的数字");intshanchush=in.nextInt();intb=a.length;intd=0,c=0,e=0;;for(inti=0;i<b;i++){if(a[i]==shanchush){e++;}}if(e>0){for(intj=0;j<e;j++){for(inti=0;i<a.length;i++){if(a[i]==shanchush){d=i;c++;break;}}for(inti=d;i<a.length-c;i++){a[i]=a[i+1];}a[a.length-1]=0;b--;}System.out.print("之后的数组：");for(inti=0;i<b;i++){System.out.print(a[i]+"");}}else{System.out.println("没有要删除的数字");}}}importjava.util.Scanner;publicclass数组插入元素2{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);float[]a={3,2,5,5,1,5,5,5,9};System.out.print("之前的数组：");for(floatx:a){System.out.print(x+"");}System.out.println();System.out.println("请输入要插入的数，及其下标位置");floatc=in.nextInt();intd=in.nextInt();floatfloat[]b=newfloat[a.length+1];for(inti=0;i<b.length;i++){if(i<d){b[i]=a[i];}if(i==d){b[i]=c;}if(i>d){b[i]=a[i-1];}}System.out.print("之后的数组：");for(inti=0;i<b.length;i++){System.out.print(b[i]+"");}}}importjava.util.Scanner;publicclass数组插入元素{publicstaticvoidmain(String[]args){DOint[]a={1,2,3,4,5,7,8,9};int[]b=newint[a.length+1];Scannerin=newScanner(System.in);System.out.println("请输入要插入的数");intc=in.nextInt();dijia:for(inti=0;i<a.length;i++){if(c<=a[i]){//当c比a[i]小就可以在数组中插入元素b[i]=c;for(intj=i;j<b.length-1;j++){b[j+1]=a[j];}breakdijia;}else{b[i]=a[i];}}if(b[b.length-1]<c){b[b.length-1]=c;}for(inti=0;i<b.length;i++){System.out.println(b[i]+"");}}}importimportjava.util.Scanner;publicclass统计某班Java成绩的不及格率{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);intb=0;doublecount=0;System.out.println("请输入班级人数");b=in.nextInt();double[]a=newdouble[b];doublen=0;System.out.println("请输入班级成绩");for(inti=0;i<a.length;i++){n=in.nextDouble();a[i]=n;}for(inti=0;i<a.length;i++){if(a[i]<60){count++;}}if(count>0){System.out.println("班级不及格率为"+((count/b)*100)+"%");}else{System.out.println("班级没有不及格的同学");}}importimportjava.util.Scanner;publicclass借用任何一种算法对数组排序{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);intn=0;System.out.println("请输入要排序的班级人数");n=in.nextInt();int[]a=newint[n];System.out.println("请输入班级成绩");for(inti=0;i<a.length;i++){n=in.nextInt();a[i]=n;}}for(inti=1;i<a.length;i++){for(intj=0;j<a.length-i;j++){if(a[j]>a[j+1]){intb;b=a[j];a[j]=a[j+1];a[j+1]=b;}}}for(inti=0;i<a.length;i++){System.out.println(a[i]+"");}}}publicpublicclass输出数组元素{//TODO自动生成的方法存根inta[][]={{8,1},{3,5,7,3},{4,9,2}};ngthifor(intj=0;j<a[i].length;j++){j}}}}(2)求每个班的平均分。图某年级Java考试成绩表publicpublicclass数据分析{publicstaticvoidmain(String[]args){DOdoublescore[][]={{99,68,97},{89,95,88,59,64},{89,79,99,58},{59,79,85,68,85}};doublesum=0;inta=0;for(inti=0;i<score.length;i++){for(intj=0;j<score[i].length;j++){sum+=score[i][j];}a+=score[i].length;}System.out.println("全年级的平均分是"+(sum/a));for(inti=0;i<score.length;i++){sum=0;for(intj=0;j<score[i].length;j++){sum+=score[i][j];}System.out.println((i+1)+"班的平均分是"+(sum/score[i].length));}}}importjava.util.Scanner;publicclass杨辉三角{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);System.out.println("请输入杨辉三角层数");intn=in.nextInt();inta[][]=newint[n][];for(inti=0;i<n;i++){a[i]=newint[i+1];}for(inti=0;i<n;i++){a[i][0]=1;a[i][i]=1;}for(inti=2;i<n;i++){for(intj=1;j<i;j++){aa[i][j]=a[i-1][j]+a[i-1][j-1];}}for(inti=0;i<n;i++){for(intj=0;j<i+1;j++){System.out.print(a[i][j]+"");}System.out.println();}}}importimportjava.util.Scanner;publicclass输出数组对角线{publicstaticvoidmain(String[]args){DOScannerin=newScanner(System.in);inta[][]=newint[3][3];for(inti=0;i<a.length;i++){for(intj=0;j<a[i].length;j++){a[i][j]=in.nextInt();}}for(inti=0;i<a.length;i++){System.out.println(a[i][i]);}System.out.println();for(inti=2;i>=0;i--){System.out.println(a[i][2-i]);}}}publicclass矩阵转制{publicstaticvoidmain(String[]args){DOint[][]a={{1,2,3,4},{5,6,7,8},{9,10,11,12}};int[][]b=newint[a.length][a.length];int[][]d=newint[4][3];for(inti=0;i<a.length;i++){for(intj=0;j<a[i].length;j++){d[j][i]=a[i][j];}}for(inti=0;i<d.length;i++){for(intj=0;j<d[i].length;j++){SystemSystem.out.print(d[i][j]+"");}System.out.println();}}}publicclass班级方差{staticdoubleqiuhe(double[]b){doublesum=0;for(inti=0;i<b.length;i++)sum=sum+b[i];returnsum;}staticdoublepingjunzhi(double[]b){doublemean=0;mean=qiuhe(b)/b.length;returnmean;}//总体方差staticdoublefangcha(double[]b){doublefangcha=0;doublec=pingjunzhi(b);for(inti=0;i<b.length;i++){fangcha=fangcha+(Math.pow((b[i]-c),2));}fangcha=fangcha/(b.length-1);returnfangcha;}publicstaticvoidmain(String[]args){DOdoublea[]={89,95,88,59,64};doubleb[]={89,79,90,58};doublef=fangcha(a),g=fangcha(b);if(pingjunzhi(a)>pingjunzhi(b)){System.out.println("1班赢了");}elseif(pingjunzhi(a)<pingjunzhi(b)){System.out.println("2班赢了");}else{System.out.println("这俩平均值相同，需要比较方差");if(f>g){System.out.println("一班赢了，方差是"+fangcha(a));}elseif(f<g){System.out.println("二班赢了，方差是"+fangcha(b));}else{SystemSystem.out.println("这俩方差都一样，太离谱了，方差是"+fangcha(a));}}System.out.println("这方差都一样，方差是"+fangcha(a));System.out.println("这方差都一样，方差是"+fangcha(b));}}publicclass学生类{publicstaticvoidmain(String[]args){//TODO自动生成的方法存根student1a=newstudent1();a.setName("小明");a.setBj("翻斗幼儿园大班");System.out.println();System.out.println(a.banji);}}classstudent1{Stringname;Stringbanji;voidsetName(Stringname){=name;}voidsetBj(Stringbanji){this.banji=banji;}}进importimportjava.util.Scanner;publicclass汽车类{public}class}}car12{Stringdoubledouble}staticvoidmain(String[]args){//TODO自动生成的方法存根car12wuling=newcar12();Scannerin=newScanner(System.in);System.out.println("原先的价格:");System.out.println(wuling.Jiage);System.out.println("请输入想要的折扣");intzhekou=in.nextInt();System.out.println("打折后的价格:");System.out.println(wuling.zhekou(zhekou));Chepai;Jiage=99999;zhekou(doublen){returnJiage*n/10;3.模拟银行账户业务publicpublicclass银行类{publicstaticvoidmain(String[]args){//TODO自动生成的方法存根Accounta=newAccount();System.out.println(a.chakan());a.cunkuan(12345);a.quqian(12347);}}classAccount{doublemoney;voidcunkuan(doublemoney){this.money+=money;System.out.println("存款成功，余额为"+money+"元");}voidquqian(doublemoney){if(this.money>=money){this.money-=money;System.out.println("取款成功，余额为"+money+"元");}else{System.out.println("余额不足，请充值");}}doublechakan(){returnmoney;}}}4.4.定义一个手机(Phone)类，在类中定义品牌(brand)和价格(price)属性，定义发短信和打电话的importjava.util.Scanner;publicclass手机类{publicstaticvoidmain(String[]args){//TODO自动生成的方法存根phoneyali=newphone("鸭梨手机",8848);System.out.println("手机品牌是"+yali.brand);System.out.println("手机价格是"+yali.price);}}classphone{Stringbrand;doubleprice;phone(Stringbrand,doubleprice){this.brand=brand;this.price=price;}voidcall(){System.out.println("这条函数语句说明我会打电话");}voidsendMessage(){System.out.println("这条函数语句说明我会发短信");}}承用法类的继承中this、super关键字的用法y}{}tx}}}}2.阅读程序，分析程序的输出结果。A:f()B:f()B:f()3.定义一个矩形类，它包含两个数据成员：长和宽，以及包含用于求面积的成员方法。再定义矩形类的子类—长的体分析：这个题目我们在前面学习类与对象时，采用了面向对象的思想这样实现的：第第一步：封装长方形的类第第二步：封装长方体类第三步：测试类第三步：测试类请用刚学习的继承来实现长方体类的定义。publicclass长方体类{publicstaticvoidmain(String[]args){DOchangfangtia=newchangfangti(3,4,5);System.out.println(a.mianji());System.out.println(a.tiji());}}classjuxing1{doublea,b;juxing1(doublea,doubleb){this.a=a;this.b=b;}doublemianji(){returna*b;}}classchangfangtiextendsjuxing1{doublegao;doublemianji;changfangti(doublea,doubleb,doublegao){super(a,b);this.gao=gao;}doubletiji(){returnmianji()*gao;}}}4.借用继承，根据下面的类图优化电子宠物系统。classpet{privateStringname;pet(Stringname){this.name=name;}publicStringgetName(){returnname;}publicvoidsetName(Stringname){this.name=name;}publicvoideat(){System.out.println(this.name+"开始干饭");}publicvoidjies