我不知道为什么这个 java 代码不起作用

Question

好的，所以我做了一个逃离房间的程序，但是灯光的布尔值不起作用

class Main {
  public static void main(String[] args) {
  System.out.println("Welcome To The Hogwarts Escape Room");
  System.out.println("To Play The Hogwarts Escape Room Press Y");
  Scanner sc = new Scanner(System.in);
  String useranswer = sc.nextLine();
  boolean light = false;
// This is not my entire code but the part that was necessary. 
  System.out.println("Press U to look up");
useranswer = sc.nextLine();
if (usernaswer.equals("U"){
System.out.println(" You look above you and see nothing as the ceiling is too dark to see in.");
    System.out.println("Would you like to: \n Look Closer press A \n Return To Your Original Position press B");
    useranswer = sc.nextLine();
    System.out.println(light);
// this part doesn't work.. I checked and made sure the useranswer was A and the boolean does equal to false.
    if (useranswer.equals("A")&&(light = false)){
      ceilingCloserlightFalse(sc, useranswer, inventory, light);
    }
    else if (useranswer.equals("B")){
      original(sc, useranswer, inventory, light);
    }
// this was the setup to the constructor

public static void ceilingCloserlightFalse(Scanner sc, String useranswer, String [] inventory, boolean light){
    System.out.println("You go closer and see something faintly but cant tell what it is without a light");
    System.out.println("You returned to the original position because there was nothing else to do there.");
    original(sc, useranswer, inventory, light);
    
  }
    
  }
}

好的所以我想知道我是否在方法或 && 运算符上做错了什么。我检查以确保 useranswer 是 a 并且我还检查以确保

Answer 1

在这里你将 false 赋值给变量，而不是比较它：

if (useranswer.equals("A")&&(light = false)){
      ceilingCloserlightFalse(sc, useranswer, inventory, light);
    }

您想使用 ==，而不是 =。此外，考虑到 useranswer 可能为 null，因此您应该 "A".equals(useranswer) 以避免 NullPointerException

Answer 2

一些开发人员使用 Yoda speak 来避免我们在这里遇到的常见错误。

而不是：

if (useranswer.equals("A")&&(light = false)){
      ceilingCloserlightFalse(sc, useranswer, inventory, light);
}

像这样向后写比较

if (useranswer.equals("A")&&(false = light)){
      ceilingCloserlightFalse(sc, useranswer, inventory, light);
}

然后你会得到一个编译器错误，指出你使用的是 = 而不是 ==。

我不知道为什么这个 java 代码不起作用

I have no idea why this java code doesn't work

java

operators