Question

这是代码 -

GHCi> :{
GHCi| flip runReader 3 $
GHCi|     return 2 >>= \x ->
GHCi|     Reader (\r -> x ^ r) >>= \y ->
GHCi|     Reader (\r -> y - r)
GHCi| :}
5
GHCi> :{
GHCi| extract $
GHCi|     Env (3, 2) =>> (\w ->
GHCi|     (\(r, x) -> x ^ r) $ runEnv w) =>> (\z ->
GHCi|     (\(r, x) -> x - r) $ runEnv z)
GHCi| :}
5

这个错误即将到来

     import java.util.Scanner;
    public class HelloWorld{

     public static void main(String []args){
    Scanner kb=new Scanner(System.in);
    System.out.println("enter a four digit number");
    int number=kb.nextInt();
    int digit2=number;

    switch (digit1)
    {
        case 1: System.out.println("One");break;
        case 2: System.out.println("Two");break;
        case 3: System.out.println("Three");break;
        case 4: System.out.println("Four");break;
        case 5: System.out.println("Five");break;
        case 6: System.out.println("Six");break;
        case 7: System.out.println("Seven");break;
        case 8: System.out.println("Eight");break;
        case 9: System.out.println("Nine");break;
        case 0: System.out.println("Zero");break;
        default: System.out.println("");break;
    }
    switch (digit2)
        {
            case 1: System.out.println("One");break;
        case 2: System.out.println("Two");break;
        case 3: System.out.println("Three");break;
        case 4: System.out.println("Four");break;
        case 5: System.out.println("Five");break;
        case 6: System.out.println("Six");break;
        case 7: System.out.println("Seven");break;
        case 8: System.out.println("Eight");break;
        case 9: System.out.println("Nine");break;
        case 0: System.out.println("Zero");break;
        default: System.out.println("");break;
        }
     }
}

请帮帮我

Answer 1

您尚未定义名为digit1的变量。

这里有一些粗略的代码可以做你想要的：

import java.util.Scanner;

public class Test {

   public static void main(String[] args) {
      Scanner kb = new Scanner(System.in);
      System.out.println("Enter a four digit number");

      String numStr = kb.next();

      int number = 0;
      try {
         number = Integer.parseInt(numStr);
      } catch (Exception e) {
         System.out.println("Input was not a number!");
         System.exit(1);
      }

      if (number < 1000) {
         System.out.println("Number must be at least four digits!");
         System.exit(1);
      }

      for (int digitNdx = 0; digitNdx < 4; digitNdx++) {
         switch (numStr.charAt(digitNdx)) {
            case '1':
               System.out.println("One");
               break;
            case '2':
               System.out.println("Two");
               break;
            case '3':
               System.out.println("Three");
               break;
            case '4':
               System.out.println("Four");
               break;
            case '5':
               System.out.println("Five");
               break;
            case '6':
               System.out.println("Six");
               break;
            case '7':
               System.out.println("Seven");
               break;
            case '8':
               System.out.println("Eight");
               break;
            case '9':
               System.out.println("Nine");
               break;
            case '0':
               System.out.println("Zero");
               break;
            default:
               System.out.println("");
               break;
         }
      }
   }
}

Answer 2

您的代码

    public class Person
    {
        public int Id { get; set; }
        public string Firstname { get; set; }
        public string Lastname { get; set; }
        public Dictionary<long,float> No {get;set;}
        public DateTime BirthDate { get; set; }
    }

    public class Manager
    {
        public int Id { get; set; }
        public User User { get; set; }
        public List<User> Users { get; set; }
    }

    public class User
    {
        public int Id { get; set; }
        public Person Person { get; set; }
        public List<string> Phones { get; set; }

    }

由于

而发生错误

此处没有为Scanner kb = new Scanner(System.in); System.out.println("enter a four digit number"); int number = kb.nextInt(); int digit2 = number; switch (digit1) {
分配任何变量

实施例

digit1

java eclipse中switch语句中的错误

2 个答案: