在Switch菜单上使用do-while循环

Question

如果在使用do while循环提示“请输入您的模块选择”时选择除1 - 11之外的任何字符，我正在尝试使程序返回菜单列表...

目前，即使用户没有选择有效选项，程序也会继续运行

我希望在“请选择一个有效的模块”之后返回菜单列表。

Scanner scanner = new Scanner(System.in);public void moduleSelection() {


    System.out.println("1\t Algorithms");
    System.out.println("2\t Advanced Programming");
    System.out.println("3\t Computer Architecture and Operating Systems");
    System.out.println("4\t Artificial intelligence and Machine Learning");
    System.out.println("5\t Computer and Mobile Networks");
    System.out.println("6\t Software Engineering");
    System.out.println("7\t Big Data Analyics");
    System.out.println("8\t Cyber Security Threats");
    System.out.println("9\t Research Methods");
    System.out.println("10\t Research Project Proposal");
    System.out.println("11\t Individual Research Project");


    System.out.println("Please entire your Module choice");

    int choice;

    choice = scanner.nextInt();

    switch (choice)
    {
    case 1: System.out.println("Algorithms");
    break;
    case 2: System.out.println("Advanced Programming");
    break;
    case 3: System.out.println("Computer Architecture and Operating Systems");
    break;
    case 4: System.out.println("Artificial intelligence and Machine Learning");
    break;
    case 5: System.out.println("Computer and Mobile Networks");
    break;
    case 6: System.out.println("Software Engineering");
    break;
    case 7: System.out.println("Big Data Analytics");
    break;
    case 8: System.out.println("Cyber Security Threats");
    break;
    case 9: System.out.println("Research Methods");
    break;
    case 10: System.out.println("Research Project Proposal");
    break;
    case 11: System.out.println("Individual Research Project");
    break;
    default: System.out.println("Please select a valid Module");
    break;
    }}

Answer 1

一个。定义变量以验证用户是否输入了validNumber。湾 在do while循环中，检查数字是否有效例如：do{System.out.println("Please entire your Module choice");int choice;choice = scanner.nextInt();boolean invalidChoice=false;switch (choice){case 1:...break;case 2:...break;default: invalidChoice=true;print ("Please enter valid choice");} while(invalidChoice);

Answer 2

public void moduleSelection() {boolean switch;do{switch = false;System.out.println("1\t Algorithms");System.out.println("2\t Advanced Programming");System.out.println("3\t Computer Architecture and Operating Systems");System.out.println("4\t Artificial intelligence and Machine Learning");System.out.println("5\t Computer and Mobile Networks");System.out.println("6\t Software Engineering");System.out.println("7\t Big Data Analyics");System.out.println("8\t Cyber Security Threats");System.out.println("9\t Research Methods");System.out.println("10\t Research Project Proposal");System.out.println("11\t Individual Research Project");System.out.println("Please entire your Module choice");int choice;choice = scanner.nextInt();switch (choice){case 1: System.out.println("Algorithms");break;case 2: System.out.println("Advanced Programming");break;case 3: System.out.println("Computer Architecture and Operating Systems");break;case 4: System.out.println("Artificial intelligence and Machine Learning");break;case 5: System.out.println("Computer and Mobile Networks");break;case 6: System.out.println("Software Engineering");break;case 7: System.out.println("Big Data Analytics");break;case 8: System.out.println("Cyber Security Threats");break;case 9: System.out.println("Research Methods");break;case 10: System.out.println("Research Project Proposal");break;case 11: System.out.println("Individual Research Project");break;default: System.out.println("Please select a valid Module");switch = true;break;}}while(switch)}

Answer 3

您可以使用标签：    loop:    while (true) {        System.out.println("Please entire your Module choice");        int choice;        choice = scanner.nextInt();        switch (choice) {            case 1:                System.out.println("Algorithms");                break loop;            case 2:                System.out.println("Advanced Programming");                break loop;            case 3:                System.out.println("Computer Architecture and Operating Systems");                break loop;            case 4:                System.out.println("Artificial intelligence and Machine Learning");                break loop;            case 5:                System.out.println("Computer and Mobile Networks");                break loop;            case 6:                System.out.println("Software Engineering");                break loop;            case 7:                System.out.println("Big Data Analytics");                break loop;            case 8:                System.out.println("Cyber Security Threats");                break loop;            case 9:                System.out.println("Research Methods");                break loop;            case 10:                System.out.println("Research Project Proposal");                break loop;            case 11:                System.out.println("Individual Research Project");                break loop;        }    }}

Answer 4

根据我作为评论的一部分添加的假设，最好为用户添加帮助文本，例如“请整个模块选择（1-11）”int choice=0;boolean isChoiceValid ;public void moduleSelection() {while(!isChoiceValid) {System.out.println("1\t Algorithms");System.out.println("2\t Advanced Programming");System.out.println("3\t Computer Architecture and Operating Systems");System.out.println("4\t Artificial intelligence and Machine Learning");System.out.println("5\t Computer and Mobile Networks");System.out.println("6\t Software Engineering");System.out.println("7\t Big Data Analyics");System.out.println("8\t Cyber Security Threats");System.out.println("9\t Research Methods");System.out.println("10\t Research Project Proposal");System.out.println("11\t Individual Research Project");System.out.println("Please entire your Module choice (1-11)");choice = scanner.nextInt();if(choice>=1 && choice<=11){isChoiceValid =true;}}