作出修正，需要執行切換聲明並提示用戶輸入歌曲選擇

Question

我正在編寫一個程序，通知用戶有一架大鋼琴並給了他們播放它的選項，但是，一旦用戶選擇了y因爲是的，它詢問問題他們想播放什麼歌曲，然後將響應打印到第一首歌曲，而不是讓用戶選擇以根據用戶的選擇提示不同的響應。

下面是代碼，它編譯，但不工作，我打算順便說一句：你是不是第二系統輸出後捕獲輸入

import java.util.*; 
public class MyPiano { 
    private static final String m = null; 
    private static final String b = null; 
    private static final String c = null; 
    private static final String f = null; 
    private static final String r = null; 
    private static final String d = null; 
    //Initialize class variables. 
    private int numOfKeys; 
    private String pianoMake; 
    private String pianoModel; 
    private boolean tuned; 

    //A constructor that has specific variables assigned to it. 
    public MyPiano (int numOfKeys, String pianoMake, String pianoModel, boolean tuned) { 
     this.numOfKeys = numOfKeys; 
     this.pianoMake = pianoMake; 
     this.pianoModel = pianoModel; 
     this.tuned = tuned; 
     } 
     //Created the output that will be displayed to the user. 
    public String toString() { 
     return "There is a beautiful " + numOfKeys + " key " + pianoMake + ", " + pianoModel + " in the living room." + 
    "\nIs it tuned?: " + tuned; 
     } 

    public static void main(String args[]) { 
     //Create an instance of household item method. 
     MyPiano piano = new MyPiano (88, "Steinway & Sons", "Model M studio grand", true); 

     //Output the status of the household item. 
     System.out.println(piano.toString()); 
     Scanner input = new Scanner(System.in); 

     char letsPlayASong; 

     System.out.println("Would you like to take a stab at playing a song on the piano? Press Y or y for yes and N or n for no."); 
     char a = input.next().trim().charAt(0);  
     if(a == 'Y' || a == 'y') { 
     //change speed using switch statement 
      System.out.print("Which song would you like to play?(Beethoven's Moonlight Sonata, Beethoven's Fur Elise, or Chopin's March Funebre): Type m for Moonlight Sonata, f for Fur Elise, or r for March Funebre."); 
      if(b == m) { 
       System.out.println("This song is played in C# minor and the first three notes are: G#, C#, and E"); 
       char b = input.next().trim().charAt(0); 
       } else if(c == f) { 
       System.out.println("This song was written in A minor with the first two notes being E and D#"); 
       char c = input.next().trim().charAt(0); 
       } else { 
        if(d == r) { 
         System.out.println("This classic, otherwise known as The Funeral March, is to be played in Bb minor, however it can be very tricky!"); 
         char d = input.next().trim().charAt(0); 
         } 
        } 
     } else { 
      if (a == 'N' || a == 'n'); { 
       System.exit(0); 
       } 
      } 
     } 
    } 

Answer 1

。你可以擺脫不必要的String變量（m，f，r等）。

它應該是這樣的：

System.out.println("Which song would you like to play?(Beethoven's Moonlight Sonata, Beethoven's Fur Elise, or Chopin's March Funebre): Type m for Moonlight Sonata, f for Fur Elise, or r for March Funebre."); 
char b = input.next().trim().charAt(0); 
if(b == 'm') { 
    System.out.println("This song is played in C# minor and the first three notes are: G#, C#, and E"); 
} 
else if(b == 'f') { 
    System.out.println("This song was written in A minor with the first two notes being E and D#"); 
} 
else if(b == 'r') { 
    System.out.println("This classic, otherwise known as The Funeral March, is to be played in Bb minor, however it can be very tricky!"); 
} 

---

您還沒有使用switch語句這裏不像在註釋行 //change speed using switch statement提及。 一個 switch聲明將是這樣的：

System.out.println("Which song would you like to play?(Beethoven's Moonlight Sonata, Beethoven's Fur Elise, or Chopin's March Funebre): Type m for Moonlight Sonata, f for Fur Elise, or r for March Funebre."); 
char b = input.next().trim().charAt(0); 
switch(b) { 
    case 'm': System.out.println("This song is played in C# minor and the first three notes are: G#, C#, and E"); 
       break; 
    case 'f': System.out.println("This song was written in A minor with the first two notes being E and D#"); 
       break; 
    case 'r': System.out.println("This classic, otherwise known as The Funeral March, is to be played in Bb minor, however it can be very tricky!"); 
       break; 
} 

Answer 2

我編輯發表在我的新代碼原題的代碼，我想通了，這樣它的工作原理正是我想要過的方式。