在java中的掃描儀將不匹配我的雙變量

Question

我已經搜索了大約一個小時，並且還沒有找到解決我的問題。我試圖使用我的掃描器變量輸入來稍後將它用於我的開關參數，但是我現在被困在第二行上，正確的語法是爲了讓我的問題正常工作。 這裏是我的Java問題：

//創建KW輸入掃描儀

Scanner kw = new Scanner(System.in); 
    double kwUsed = kw; 

    //Verify if KW is valid 
    try 
    { 
     //KW used data entry 
     System.out.println("Please enter KW used: "); 
     kwUsed = kw.nextDouble(); 
     System.out.println("KW entry valid"); 
    } 
    catch (Exception error) 
    { 
     System.out.println("Invalid entry"); 
     System.out.println(error); 
    } 

    //Date entry will be calculated by how much KW user enters 
    switch (input) 
    { 
     case "2/15/13": 
      double quarter1 = kwUsed * 0.10; 
      break; 
     case "4/15/13": 
      double quarter2 = kwUsed * 0.12; 
      break; 
     case "8/15/13": 
      double quarter3 = kwUsed * 0.15; 
      break; 
     case "11/15/13": 
      double quarter4 = kwUsed * 0.15; 
      break; 
     default: 
      System.out.println("Invalid date"); 

    } 

Answer 1

只想常說我不會只是修復某人的代碼，然後將其粘貼，但在這種情況下，我覺得它的更好地讓OP看到一些製造的小錯誤，而不是漫不經心。

import java.util.Scanner; 
import java.io.IOException; 
import java.io.FileReader; 
import java.io.File; 
import java.io.BufferedReader; 

public class MainTest { 
    public static void main(String[] args) { 

     Scanner kw = new Scanner(System.in); 
     double kwUsed = 0; 

     // Verify if KW is valid 
     try { 

      // KW used data entry 
      System.out.println("Please enter KW used: "); 
      kwUsed = kw.nextDouble(); 
      System.out.println("KW entry valid"); 
     } catch (Exception error) { 
      System.out.println("Invalid entry"); 
      System.out.println(error); 
     } 

     // Date entry will be calculated by how much KW user enters 
     String input; 
     System.out.println("Enter input case"); 
     input = kw.next(); 

     switch (input) { 
     case "2/15/13": 
      double quarter1 = kwUsed * 0.10; 
      break; 
     case "4/15/13": 
      double quarter2 = kwUsed * 0.12; 
      break; 
     case "8/15/13": 
      double quarter3 = kwUsed * 0.15; 
      break; 
     case "11/15/13": 
      double quarter4 = kwUsed * 0.15; 
      break; 
     default: 
      System.out.println("Invalid date"); 

     } 
      //handle your quarter1-4 here 
    } 
}