java基础作业1附答案

./X<x<1>Y=2x-1<1<x<10>3x-11<x>10>要求输入x值后,输出y值。packagestudent.xiaoqiao.day01;importjava.util.Scanner；publicclassYi{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个数">; Scannersc=newScanner<System.in>; intx=sc.nextInt<>; if<x<1>{ System.out.println<"y="+x>; } if<x>1&x<10>{ System.out.println<"y="+<2*x-1>>; } if<x>10>{ System.out.println<"y="+<3*x-11>>; } }}输入一个年份判断year是否是闰年packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassEr{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入年份">; Scannersc=newScanner<System.in>; intyear=sc.nextInt<>; if<<year%4==0&year%100!=0>|<year%400==0>> System.out.println<"是闰年">; else System.out.println<"不是闰年">; }}任意输入a,b,c3个数判断a,b,c大小packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassSan{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入三个数〔加空格或回车:">; Scannersc=newScanner<System.in>; intx=sc.nextInt<>; inty=sc.nextInt<>; intz=sc.nextInt<>; if<x>y&x>z>{ System.out.println<x>; }elseif<x<y&z<y>{ System.out.println<y>; }elseif<x<z&y<z>{ System.out.println<z>; } }}4_1输出图形*********packagestudent.xiaoqiao.day01;publicclassSi_1{ publicstaticvoidmain<String[]args>{ inttemp=3; for<inti=1;i<=temp;i++>{ for<intj=1;j<=temp-i;j++>{ System.out.print<"">; } for<intk=1;k<=2*i-1;k++>{ System.out.print<"*">; } System.out.print<'\n'>; } }}4_2输出图形*********packagestudent.xiaoqiao.day01;publicclassSi_1{ publicstaticvoidmain<String[]args>{ inttemp=3; for<inti=1;i<=temp;i++>{ for<intj=1;j<=temp-i;j++>{ System.out.print<"">; } for<intk=1;k<=2*i-1;k++>{ System.out.print<"*">; } System.out.print<'\n'>; } }}4_3输出图形任意输入n当输入n值为1时,输出*当输入n值为2时,输出当输入n值为3时,输出.。。。。。当输入n值为5时,输出*****************************************packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassSi_3{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个数：">; Scannersc=newScanner<System.in>; inttemp=sc.nextInt<>; for<inti=1;i<=temp;i++>{ for<intj=1;j<=temp-i;j++>{ System.out.print<"">; } for<intk=1;k<=2*i-1;k++>{ System.out.print<"*">; } System.out.print<'\n'>; } for<inti=temp;i>=1;i-->{ for<intj=i-1;j<temp;j++>{ System.out.print<"">; } for<intk=1;k<=2*i-3;k++>{ System.out.print<"*">; } System.out.print<'\n'>; } }}4_4输出图形***************packagestudent.xiaoqiao.day01;publicclassSi_4{ publicstaticvoidmain<String[]args>{ inttemp=3; for<inti=1;i<=temp;i++>{ for<intj=1;j<=temp-i;j++>{ System.out.print<"">; } for<intk=1;k<=2*i+1;k++>{ System.out.print<"*">; } System.out.print<'\n'>; } }}4_5输出图形packagestudent.xiaoqiao.day01;publicclassSi_5{ publicstaticvoidmain<String[]args>{ inttemp=4; for<inti=1;i<=temp;i++>{ for<intk=1;k<=5;k++>{ System.out.print<"*">; } System.out.print<'\n'>; } }}判断水仙花数输入一个3位数,判断个位,十位与百位的3次方的和是否等于其本身,相等就是水仙花数packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassWu{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个三位数">; Scannersc=newScanner<System.in>; inta=sc.nextInt<>; intb=a/100; intc=<a/10>%10; intd=a%10; if<a==b*b*b+c*c*c+d*d*d>{ System.out.println<"此数是水仙花">; }else{ System.out.println<"此数不是水仙花">; } }}6.输入一个x和y,在输入一个字符x,当输入的字符为‘+’,输出x与y的和,当输入的字符为‘-’,输出x与y的差,当输入的字符为‘*’,输出x与y的积,当输入的字符为‘/’,输出x与y的商.packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassLiu{ publicstaticvoidmain<String[]args>{System.out.println<"请输入一个加减乘除字符">; Scannersc=newScanner<System.in>; charc=sc.next<>.charAt<0>; intx=4; inty=2; switch<c>{ case'+': System.out.println<"x+y="+<x+y>>; break; case'-': System.out.println<"x-y="+<x-y>>; break; case'*': System.out.println<"x*y="+<x*y>>; break; case'/': System.out.println<"x/y="+<x/y>>; break; default: System.out.println<"输入的字符不合法！">; break; } }}7.求数列0,1,2,32,…………….,nn-1的和要求判断n是否在0到10之间,如果不在提示重新输入,for循环while循环,dowhile都要写一遍。7.1packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassQi{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个0到10的数字">; Scannersc=newScanner<System.in>; inta=sc.nextInt<>; if<a>=0&a<=10>{ intb=0; for<inti=1;i<=a;i++>{ b=<int><b+Math.pow<i,i-1>>; } System.out.println<b>; } else{ System.out.println<"输入的数不在0到10之间,请重新输入！">; } }};importjava.util.Scanner;publicclassQi_dowhile{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个0到10的数字">; Scannersc=newScanner<System.in>; inta=sc.nextInt<>; if<a>=0&a<=10>{ intb=0; inti=1; do{ b=<int><b+Math.pow<i,i-1>>; i++; } while<i<=a>; System.out.println<b>; } else{ System.out.println<"输入的数不在0到10之间,请重新输入！">; } }}7.3packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassQi_while{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个0到10的数字">; Scannersc=newScanner<System.in>; inta=sc.nextInt<>; if<a>=0&a<=10>{ intb=0; inti=1; while<i<=a>{ b=<int><b+Math.pow<i,i-1>>; i++; } System.out.println<b>; } else{ System.out.println<"输入的数不在0到10之间,请重新输入！">; } }}8输出9*9乘法表packagestudent.xiaoqiao.day01;publicclassBa{ publicstaticvoidmain<String[]args>{ for<inti=1;i<=9;i++>{ for<intj=1;j<=i;j++>{ System.out.print<i+"*"+j+"="+i*j+"">; } System.out.print<'\n'>; } }}9.输入x,y比较大小,使用三目运算packagestudent.xiaoqiao.day01;importjava.util.Scanner;publicclassJiu{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入两个值：">; Scannersc=newScanner<System.in>; intx=sc.nextInt<>; inty=sc.nextInt<>; System.out.println<x>y?"x大于y":"x小于y">; }}Day02作业题目：编写程序实现一个猜数字游戏：系统随机生成一个100以的整数,用户根据系统提示来进行猜测,如果猜对,则显示"恭喜"并提示"增加难度,需要继续吗？",如果用户选择继续则系统随机生成一个1000以的整数,否则系统退出；如果用户猜错,则显示"错误,请重新输入！",一旦用户连续5次没有猜中,则系统退出！packagestudent.xiaoqiao.Day02;importjava.util.Scanner;importjava.util.concurrent.CountDownLatch;publicclassRandomdemo{ publicstaticvoidmain<String[]args>{ inta=<int><Math.random<>*100>+1;//系统随机生成一个1到100的整数 System.out.println<a>; System.out.println<"请输入一个1到100的整数">; Scannersc1=newScanner<System.in>;//从键盘上输入一个数 intnum1=sc1.nextInt<>; while<num1!=a>{ if<num1>a>{ System.out.println<"您输入的数字过大,请重新输入!">; } if<num1<a>{ System.out.println<"您输入的数字过小,请重新输入!">; } num1=sc1.nextInt<>; } if<num1==a>{ System.out.println<"小主好棒,您猜对啦！！"+'\r'+"请问还要升级难度吗〔随机生成1到1000的整数,继续请输入‘是’,退出选择‘否’。"+'\r'>; charch=sc1.next<>.charAt<0>; if<ch=='是'>{ intb=<int><Math.random<>*1000>+1;//系统随机生成一个1到1000的整数 System.out.println<b>; System.out.println<"请输入一个1到1000的整数">; intnum2=sc1.nextInt<>; intcount=1; while<num2!=b&count<5>{ System.out.println<"错误,请重新输入!">; num2=sc1.nextInt<>; count++; } if<num2==b>{ System.out.println<"您已输入超过五次,游戏结束！">; } } if<ch=='否'>{ System.out.println<"游戏结束！">; } } }}歌手找打分：在歌唱比赛中,共有10位评委进行打分,在计算歌手得分时,去掉一个最高分,去掉一个最低分,然后剩余的8位评委的分数进行平均,就是该选手的最终得分,输入每个评委的评分,求某选手的得分。packagestudent.xiaoqiao.Day02;importjava.awt.peer.SystemTrayPeer;importjava.util.Scanner;publicclassGrade{ publicstaticvoidmain<String[]args>{ int[]qiao=newint[10]; System.out.println<"请输入十位评委成绩<回车确认>：">; Scannerscanner=newScanner<System.in>; for<inti=0;i<10;i++>{ qiao[i]=scanner.nextInt<>;// if<i==9>{// System.out.println<"停止输入！">;// } } for<inti=0;i<qiao.length;i++>{ for<intj=i+1;j<qiao.length;j++>{ if<qiao[i]<qiao[j]>{ inttemp=qiao[i]; qiao[i]=qiao[j]; qiao[j]=temp; } }// System.out.print<qiao[i]+"">; } intsum=0; for<inti=1;i<9;i++>{ sum=sum+qiao[i]; } System.out.println<sum/8.0>; }}1./**字符串——比较空间的里值,*1、输入89.9543四舍五入<1>保留2位<2>取整四舍五入math方法packagestudent.xiaoqiao.Day02;publicclassYi_sishewuru{ publicstaticvoidmain<String[]args>{ doublea=89.9543; System.out.println<Math.round<a*100>/100.0>; System.out.println<Math.round<a>>; }}*2、已经字符串"thisisatestofjava"*〔1统计该字符串s出现的次数*〔2取出字符串中"test"*〔3将字符串中每个单词的第1个字符,变成大写输出。*〔4用两种方式实现该字符串的倒叙输出〔用StringBuffer和for实现*<5>算出字符串中字母、数字、空格各多少packagestudent.xiaoqiao.Day02;publicclassEr_Zifuchuan{ publicstaticvoidmain<String[]args>{ intcount=0; Stringstr="thisisatestofjava"; for<intk=0;k<str.length<>;k++>{ Stringa1=str.substring<k,k+1>; if<a1.equals<"s">>{ count++; } } System.out.println<count>; System.out.println<str.substring<10,14>>; String[]a2=str.split<"">; StringBuffera4=newStringBuffer<>; for<intk=0;k<a2.length;k++>{ a4.append<a2[k].substring<0,1>.toUpperCase<>+a2[k].substring<1>+"">; } System.out.println<a4.toString<>>; StringBuffera5=newStringBuffer<str>; System.out.println<a5.reverse<>>; for<intk=0;k<str.length<>;k++>{ System.out.print<str.substring<str.length<>-1-k,str.length<>-k>+"">; }intenglishCount=0; intspaceCount=0; intnumCount=0; char[]aa=str.toCharArray<>; for<inti=0;i<aa.length;i++>{ if<Character.isLetter<aa[i]>>{ englishCount++; } elseif<Character.isSpaceChar<aa[i]>>{ spaceCount++; } elseif<Character.isDigit<aa[i]>>{ numCount++; } } System.out.println<>; System.out.println<"字母的个数："+englishCount>; System.out.println<"空格的个数："+spaceCount>; System.out.println<"数字的个数："+numCount>; }}*3、输入某年某月某日,判断这一天是这一年的第几天<date>packagestudent.xiaoqiao.Day02;////importjava.text.SimpleDateFormat;//importjava.util.Date;//publicclassSan_Date{// publicstaticvoidmain<String[]args>{// Dated=newDate<>;// SimpleDateFormatsim=newSimpleDateFormat<"yyyy-MM-ddHH:mm:ss">;// Stringss=sim.format<d>;// System.out.println<ss>; // }//}importjava.text.ParseException;importjava.text.SimpleDateFormat;importjava.util.Calendar;importjava.util.Date;importjava.util.Scanner;publicclassSan_Date{ publicstaticvoidmain<String[]args>{try{ Scannersc=newScanner<System.in>; System.out.print<"输入时间<格式:yyyy-MM-dd>">; Stringstr=sc.nextLine<>; SimpleDateFormatf=newSimpleDateFormat<"yyyy-MM-dd">; Dated=f.parse<str>; Calendarc=Calendar.getInstance<>; c.setTime<d>; System.out.println<str+"是这一年的第"+c.get<Calendar.DAY_OF_YEAR> +"天">; }catch<ParseExceptione>{ e.printStackTrace<>; } }}*4、输入3个数由小到大的排序importjava.util.Scanner;publicclassSi_paixu{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入三个数：">; int[]qiao=newint[3]; Scannerscanner=newScanner<System.in>; for<inti=0;i<3;i++>{ qiao[i]=scanner.nextInt<>; } for<inti=0;i<qiao.length;i++>{ for<intj=i+1;j<qiao.length;j++>{ if<qiao[i]>qiao[j]>{ inttemp=qiao[i]; qiao[i]=qiao[j]; qiao[j]=temp; } } System.out.print<qiao[i]+"">; } }}*5、编写一个截取字符串的函数,输入为一个字符串和字节数输出为按字截取的字符串。但是要保证汉字不被截半个,如："我ABC"4,应该截为"我AB",输入"我ABC汉DEF"6,*应该输出为"我ABC",而不是ABC+汉的半个。〔有点复杂可以先做别的*/package.day02;publicclassTest05{ publicstaticvoidmain<String[]args>{ //TODOAuto-generatedmethodstub Stringss=getString<"s我是DW",4>;//调用 ss=getString<"我ABC汉DEF",6>; System.out.println<ss>;//拼接 // StringBuffersss=newStringBuffer<>;// sss.append<"akd">;// sss.append<ss.charAt<0>>; } publicstaticStringgetString<Strings,intn>{ intindex=0;//定义游标位置 StringBufferss=newStringBuffer<>;//用来存放新的值 for<inti=0;i<=n-1;i++>{ if<s.charAt<index><255&&s.charAt<index>>0||Character.isDigit<s.charAt<index>>>{//如果当前字符是数字字符 ss.append<s.charAt<index>>;//append:参数将被追加到此序列。此序列的长度将增加1。 index++; }else{ //如果当前字符是汉字 if<index<=n-2>{// ss.append<s.charAt<index>>;//charAt<index>返回指定索引处的char值。 index++; n--;//当遇到汉字以后,因汉字占两个字节,n自动减1,例如"s我"总共占3个字节,"n"代表所取字节数,这时候已经占用了3个字节,当需要取2个 //字节时,"s我"是点3个字节,"我"自动取消,当需要取4个字节时,"s我是"是占用5个字节, } } } returnss.toString<>; }}将十进制数35转换为二进制数packagestudent.xiaoqiao.Day03;publicclassLiu_shijinzhi{ publicstaticvoidmain<String[]args>{ System.out.println<Integer.toBinaryString<35>>; }}将字符串数组按字典的顺序重新排列"Java","Basic","C++","Fortran","SmallTalk"packagestudent.xiaoqiao.Day03;importjava.util.Arrays;publicclassQI_paixu{ publicstaticvoidmain<String[]args>{ String[]s=newString[5]; s[0]="Java"; s[1]="Basic"; s[2]="C++"; s[3]="Fortran"; s[4]="SmallTalk"; Arrays.sort<s>; System.out.println<Arrays.toString<s>>; }}8.输出辉三角效果图如下packagestudent.xiaoqiao.Day03;importjava.util.Scanner;publicclassBa_yanghui{ publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个整数：">; Scannersc=newScanner<System.in>; intb=sc.nextInt<>; int[][]a=newint[b][b]; for<inti=0;i<b;i++>{ a[i][i]=1; a[i][0]=1; } for<inti=2;i<b;i++>{ for<intj=1;j<i;j++>{ a[i][j]=a[i-1][j-1]+a[i-1][j]; } } for<inti=0;i<b;i++>{// for<intk=0;k<2*<2*b-i>-1;k++>{// System.out.print<"">;// } for<intj=0;j<=i;j++>{ System.out.print<a[i][j]+"">; } System.out.println<>; } }}9．〔附加题输出N*N方阵N输入为1时N输入为2时。。。。。N输入为5时/***2、假设N=5,显示5*5的方阵的转圈结果*12345*161718196*152425207*142322218*131211109**1、判断有多少个外循环,*2、四个for循环输出*/package.day03Home;importjava.util.Scanner;publicclassTest09{ publicstaticvoidmain<String[]args>{ //TODOAuto-generatedmethodstub intk=1; Scannersc=newScanner<System.in>; System.out.print<"请输入N*N方阵的数为：">; intN=sc.nextInt<>; int[][]a=newint[N][N]; for<inti=0;i<=N/2;i++> { for<intj=i;j<N-i;j++>//0-41-32-2 { a[i][j]=k++; } for<intj=i+1;j<N-i;j++>//1-42-3 { a[j][N-i-1]=k++; } for<intj=N-i-2;j>=i;j-->//3-02-1 { a[N-i-1][j]=k++; } for<intj=N-i-2;j>i;j-->//3-1 a[j][i]=k++; } for<inti=0;i<a.length;i++>{ for<intj=0;j<a.length;j++> System.out.print<a[i][j]+"\t">; System.out.println<>; } }}10.五子棋游戏11.用递归来实现5！=5*4！=5*4*3！=5*4*3*2！=5*4*3*2*1输出5！的值packagestudent.xiaoqiao.Day03;publicclassShiyi_digui{ publicstaticintfn<intn>{ if<n<=1>{ return1; } else{ returnn*fn<n-1>; } } publicstaticvoidmain<String[]args>{ System.out.println<"5!="+fn<5>>; }}12.0、1、1、2、3、5、8、13、21、34、……在数学上,斐波纳契数列以如下被以递归的方法定义：F〔0=0,F〔1=1,F〔n=F<n-1>+F<n-2>〔n≥2packagestudent.xiaoqiao.Day03;importjava.util.Scanner;publicclassShier_Fn{ publicstaticintfn<intn>{ if<n==0>{ return0; } elseif<n==1>{ return1; } else{ returnfn<n-1>+fn<n-2>; } } publicstaticvoidmain<String[]args>{ System.out.println<"请输入一个数：">; Scannerscanner=newScanner<System.in>; inta=scanner.nextInt<>; System.out.println<fn<a>>; }}1二分法.packagestudent.xiaoqiao.Day04;importjava.util.Scanner;publicclassErfen{ publicstaticvoidmain<String[]args>{ int[]a={1,21,25,44,56}; intmin=0; intmax=a.length-1; System.out.println<"请输入一个数：">; Scannerscanner=newScanner<System.in>; intb=scanner.nextInt<>; intmid=