java设计题目大全及答案

java设计题目大全及答案1.设计一个简单的Java程序，实现一个计算器的基本功能，包括加、减、乘、除。答案：```javaimportjava.util.Scanner;publicclassSimpleCalculator{publicstaticvoidmain(String[]args){Scannerscanner=newScanner(System.in);System.out.print("Enterfirstnumber:");doublenum1=scanner.nextDouble();System.out.print("Entersecondnumber:");doublenum2=scanner.nextDouble();System.out.print("Enteroperation(+,-,,/):");charoperation=scanner.next().charAt(0);doubleresult=0;switch(operation){case'+':result=num1+num2;break;case'-':result=num1-num2;break;case'':result=num1num2;break;case'/':if(num2!=0){result=num1/num2;}else{System.out.println("Cannotdividebyzero.");}break;default:System.out.println("Invalidoperation.");}if(result!=0){System.out.println("Result:"+result);}scanner.close();}}```2.设计一个Java程序，实现一个简单的文本编辑器，能够实现打开文件、保存文件、退出程序的功能。答案：```javaimportjava.io.;importjava.util.Scanner;publicclassSimpleTextEditor{publicstaticvoidmain(String[]args){Scannerscanner=newScanner(System.in);StringfilePath="";while(true){System.out.println("1.OpenFile");System.out.println("2.SaveFile");System.out.println("3.Exit");System.out.print("Enteryourchoice:");intchoice=scanner.nextInt();scanner.nextLine();//Consumenewlineleft-overswitch(choice){case1:System.out.print("Enterfilepathtoopen:");filePath=scanner.nextLine();try{Filefile=newFile(filePath);BufferedReaderreader=newBufferedReader(newFileReader(file));Stringline;while((line=reader.readLine())!=null){System.out.println(line);}reader.close();}catch(IOExceptione){System.out.println("Erroropeningfile:"+e.getMessage());}break;case2:if(!filePath.isEmpty()){try{BufferedWriterwriter=newBufferedWriter(newFileWriter(filePath));System.out.print("Entertexttosave:");Stringtext=scanner.nextLine();writer.write(text);writer.close();System.out.println("Filesavedsuccessfully.");}catch(IOExceptione){System.out.println("Errorsavingfile:"+e.getMessage());}}else{System.out.println("Nofileisopentosave.");}break;case3:System.exit(0);default:System.out.println("Invalidchoice.Pleasetryagain.");}}}}```3.设计一个Java程序，实现一个简单的银行账户管理系统，包括存款、取款、查询余额的功能。答案：```javaimportjava.util.Scanner;publicclassBankAccount{privatedoublebalance;publicBankAccount(doubleinitialBalance){this.balance=initialBalance;}publicvoiddeposit(doubleamount){balance+=amount;System.out.println("Deposited:"+amount);System.out.println("NewBalance:"+balance);}publicvoidwithdraw(doubleamount){if(amount>balance){System.out.println("Insufficientfunds.");}else{balance-=amount;System.out.println("Withdrawn:"+amount);System.out.println("NewBalance:"+balance);}}publicvoidprintBalance(){System.out.println("CurrentBalance:"+balance);}publicstaticvoidmain(String[]args){Scannerscanner=newScanner(System.in);BankAccountaccount=newBankAccount(1000);//Initialbalanceof1000while(true){System.out.println("1.Deposit");System.out.println("2.Withdraw");System.out.println("3.CheckBalance");System.out.println("4.Exit");System.out.print("Enteryourchoice:");intchoice=scanner.nextInt();scanner.nextLine();//Consumenewlineleft-overswitch(choice){case1:System.out.print("Enteramounttodeposit:");doubledepositAmount=scanner.nextDouble();account.deposit(depositAmount);break;case2:System.out.print("Enteramounttowithdraw:");doublewithdrawAmount=scanner.nextDouble();account.withdraw(withdrawAmount);break;case3:account.printBalance();break;case4:System.exit(0);default:System.out.println("Invalidchoice.Pleasetryagain.");}}}}```4.设计一个Java程序，实现一个简单的图书管理系统，包括添加图书、删除图书、查询图书的功能。答案：```javaimportjava.util.;publicclassBookManager{privateMap<String,String>books=newHashMap<>();publicvoidaddBook(Stringtitle,Stringauthor){books.put(title,author);System.out.println("Bookadded:"+title+"by"+author);}publicvoidremoveBook(Stringtitle){if(books.remove(title)!=null){System.out.println("Bookremoved:"+title);}else{System.out.println("Booknotfound:"+title);}}publicvoidsearchBook(Stringtitle){Stringauthor=books.get(title);if(author!=null){System.out.println("Bookfound:"+title+"by"+author);}else{System.out.println("Booknotfound:"+title);}}publicstaticvoidmain(String[]args){Scannerscanner=newScanner(System.in);BookManagermanager=newBookManager();while(true){System.out.println("1.AddBook");System.out.println("2.RemoveBook");System.out.println("3.SearchBook");System.out.println("4.Exit");System.out.print("Enteryourchoice:");intchoice=scanner.nextInt();scanner.nextLine();//Consumenewlineleft-overswitch(choice){case1:System.out.print("Enterbooktitle:");Stringtitle=scanner.nextLine();System.out.print("Enterbookauthor:");Stringauthor=scanner.nextLine();manager.addBook(title,author);break;case2:System.out.print("Enterbooktitletoremove:");StringremoveTitle=scanner.nextLine();manager.removeBook(removeTitle);break;case3:System.out.print("Enterbooktitletosearch:");StringsearchTitle=scanner.nextLine();manager.searchBook(searchTitle);break;case4:System.exit(0);default:System.out.println("Invalidchoice.Pleasetryagain.");}}}}```5.设计一个Java程序，实现一个简单的学生成绩管理系统，包括添加学生成绩、删除学生成绩、查询学生成绩的功能。答案：```javaimportjava.util.;publicclassStudentGradeManager{privateMap<String,Double>grades=newHashMap<>();publicvoidaddGrade(StringstudentName,doublegrade){grades.put(studentName,grade);System.out.println("Gradeaddedfor"+studentName+":"+grade);}publicvoidremoveGrade(StringstudentName){if(grades.remove(studentName)!=null){System.out.println("Graderemovedfor"+studentName);}else{System.out.println("Gradenotfoundfor"+studentName);}}publicvoidsearchGrade(StringstudentName){Doublegrade=grades.get(studentName);if(grade!=null){System.out.println("Gradefor"+studentName+":"+grade);}else{System.out.println("Gradenotfoundfor"+studentName);}}publicstaticvoidmain(String[]args){Scannerscanner=newScanner(System.in);StudentGradeManagermanager=newStudentGradeManager();while(true){System.out.println("1.AddGrade");System.out.println("2.RemoveGrade");System.out.println("3.SearchGrade");System.out.println("4.Exit");System.out.print("Enteryourchoice:");intchoice=scanner.nextInt();scanner.nextLine();//Consumenewlineleft-overs