無法在if語句中使用字符串

-4

對於這個大膽的問題，您好，非常抱歉，但我不知道如何解決我在代碼行24和30上的需求。也即時獲得第33和第22行的錯誤消息，所以如果你能解決這些問題，那將是非常棒的。無法在if語句中使用字符串

import java.util.Scanner; 

public class CheckOrder { 


    public static Scanner userInput = new Scanner(System.in); 
    public static Scanner userInputStarters = new Scanner(System.in); 

    public static String menu; 
    public static String check; 
    public static String TheRestroom = "The Restroom"; 
    public static String Restroom = "Restroom"; 
    public static String Eat = "Eat"; 
    public static String ToEat = "To Eat"; 
    public static String restOrEat; 


    public static void main(String[] args) { 

     System.out.print("Hello and Welcome to the SOMETHING restaurant. Would you like to eat or use the restroom?"); 
     public static restOrEat = userInput.NextInt(); 

     if (restOrEat.equalsIgnoreCase(TheRestroom || Restroom)) { 

      System.out.println("Please go ahead to the restroom, it's over there."); 
      System.exit(1); 
     } 

     if (restOrEat.equalsIgnoreCase(Eat || ToEat)) { 

      System.out.print("What would you like to eat for starters? Press 1 for Cheese & Bacon, 2 for Sald (With options) and 3 for noodles"); 
      public static String starter = userInputStarters; 

     } 


    } 

}

來源

2017-07-18 Dennis A Zern

請發佈一個MCCVE（如[MCVE]，但可編譯）。一些閱讀：https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#equalsIgnoreCase-java.lang.String- – 2017-07-18 11:32:15

你嘗試了一個'sys.out'並檢查。用戶輸入可能需要'trim'。 – Mritunjay

你不應該一次檢查'equalsIgnoreCase'。 – soorapadman

首先在主要方法中，您不能使用public static。聽起來像restOrEat應該是一個是或否的字符串，所以你不能說nextInt()。如果只有一個字，則使用next();如果需要整行，則使用nextLine()。並且在if語句中，您不能在equalsIgnoreCase()呼叫中使用||運營商，但需要製作兩個並將||置於中間。

試試這個，如果它符合你的需要。

import java.util.Scanner; 

public class CheckOrder { 

    public static Scanner userInput = new Scanner(System.in); 
    public static Scanner userInputStarters = new Scanner(System.in); 

    public static String menu; 
    public static String check; 
    public static String TheRestroom = "The Restroom"; 
    public static String Restroom = "Restroom"; 
    public static String Eat = "Eat"; 
    public static String ToEat = "To Eat"; 
    public static String restOrEat; 


    public static void main(String[] args) { 

     System.out.print("Hello and Welcome to the SOMETHING restaurant. Would you like to eat or use the restroom?"); 
     restOrEat = userInput.next(); 

     if (restOrEat.equalsIgnoreCase(TheRestroom) || restOrEat.equalsIgnoreCase(Restroom)) { 

      System.out.println("Please go ahead to the restroom, it's over there."); 
      System.exit(1); 
     } 

     if (restOrEat.equalsIgnoreCase(Eat) || restOrEat.equalsIgnoreCase(ToEat)) { 

      System.out.print("What would you like to eat for starters? Press 1 for Cheese & Bacon, 2 for Sald (With options) and 3 for noodles"); 
      int starter = userInputStarters.nextInt(); 

     } 


    } 

}

來源

2017-07-18 11:32:57

你會麻煩解釋它是什麼嗎？ – Mritunjay

你還沒有解釋是什麼原因造成的問題？ – soorapadman

||運算符不能應用於java.util.String。

restOrEat.equalsIgnoreCase(Eat || ToEat);

的兩個變量Eat和ToEat是從該類對象java.util.String。這就是爲什麼在這種情況下||運營商不起作用。

將其更改爲：

restOrEat.equalsIgnoreCase(Eat) || restOrEat.equalsIgnoreCase(ToEat);

這將工作。

來源

2017-07-18 11:36:48

你不能在主要方法內寫入'public static'。

if (restOrEat.equalsIgnoreCase(TheRestroom) || restOrEat.equalsIgnoreCase(Restroom)) {

與上述參考

來源

2017-07-18 11:37:45

首先把if語句是不正確的，他們應該是這樣的if (restOrEat.equalsIgnoreCase(TheRestroom) || restOrEat.equalsIgnoreCase(Restroom)) {

其次，你不能有公共和替換你都行方法內變量的靜態關鍵字。

因此改變public static restOrEat（你還缺少對象定義）int restOrEat（貌似你已經將它定義爲在類的字符串）和NextInt應該是nextInt()

還檢查了這一點Java Naming Conventions

來源

2017-07-18 11:37:58 Jockie

你有幾個問題：

或者條件（||）應該是檢查之間

if (restOrEat.equalsIgnoreCase(TheRestroom) || restOrEat.equalsIgnoreCase(Restroom)) { }

您定義restOrEat爲類變量，但它重新定義（在某種程度上）在main
```
public static restOrEat = userInput.NextInt(); 
```
public static不是方法變量有效的語法（甚至不另發），而你沒有有類型。
userInput.NextInt();將返回int但restOrEat是String。改爲使用userInput.next()。

來源

2017-07-18 11:38:26 Guy

import java.util.Scanner; 
class CheckOrder { 


public static Scanner userInput = new Scanner(System.in); 
public static Scanner userInputStarters = new Scanner(System.in); 

public static String menu; 
public static String check; 
public static String TheRestroom = "The Restroom"; 
public static String Restroom = "Restroom"; 
public static String Eat = "Eat"; 
public static String ToEat = "To Eat"; 
public static String restOrEat; 


public static void main(String[] args) { 

    System.out.print("Hello and Welcome to the SOMETHING restaurant. Would you like to eat or use the restroom?"); 
    restOrEat = userInput.next(); 

    if (restOrEat.equalsIgnoreCase(TheRestroom)||restOrEat.equalsIgnoreCase(Restroom)) { 

     System.out.println("Please go ahead to the restroom, it's over there."); 
     System.exit(1); 
    } 

    if (restOrEat.equalsIgnoreCase(Eat)||restOrEat.equalsIgnoreCase(ToEat)) { 

     System.out.print("What would you like to eat for starters? Press 1 for Cheese & Bacon, 2 for Sald (With options) and 3 for noodles"); 
     int starter = userInputStarters.nextInt(); 

    } 
} 
}

這裏是你的問題的解決方案。

來源

2017-07-19 02:41:41

無法在if語句中使用字符串

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