Question

在这里，在我的代码中，我需要检查一个具有布尔值的字符。为此，我创建了一个布尔方法并检查了字符输入，但是当我在while循环中使用此方法时，出现了一些错误。因此，现在该怎么做才能进行字符验证。我的代码看起来像-

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

        Scanner input = new Scanner(System.in);
        System.out.println("Enter your character: ");
        String operator = input.next();
        char c=operator.charAt(0);



        public static boolean isNotChar(char c){
            boolean returnValue;
            if(c != '+' || c != '-' || c != '*' || c != '/' || c != '^'){
                returnValue = true;
            }else{
                returnValue = false;
            }
            return returnValue;
        }

        boolean b1 = isNotChar(c);

        while (b1 == true){
                System.out.println("Operator doesn't match. Try again.");
                System.out.print("Enter the operator (+ - X / ^): ");
                c = input.next().charAt(0);
            }
        System.out.println("Your character is "+c);
    }
}

我的错误就像-

E:\java>javac Test.java
Test.java:14: error: illegal start of expression
                public static boolean isNotChar(char c){
                ^
Test.java:26: error: illegal start of type
                while (b1 == true){
                ^
Test.java:26: error: <identifier> expected
                while (b1 == true){
                         ^
Test.java:31: error: <identifier> expected
                System.out.println("Your character is "+c);
                                  ^
Test.java:31: error: illegal start of type
                System.out.println("Your character is "+c);
                                   ^
Test.java:33: error: class, interface, or enum expected
}
^
6 errors

我应该如何为其创建布尔方法？

代码的解决方案是：-

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

        Scanner input = new Scanner(System.in);
        System.out.println("Enter your character: ");
        String operator = input.next();
        char c=operator.charAt(0);

        boolean b1 = isNotChar(c);

        while (b1 == false){
                System.out.println("Character doesn't match. Try again.");
                System.out.print("Enter the Character from (+ - X / ^): ");
                c = input.next().charAt(0);
                b1 = isNotChar(c);
            }
        System.out.println("Your character is "+c);
    }

    public static boolean isNotChar(char c){

        boolean returnValue;

        if(c != '+' && c != '-' && c != '*' && c != '/'){
            returnValue = false;
        }else{
            returnValue = true;
        }
        return returnValue;
    }
}

Answer 1

如注释中所述，将isNotChar方法从main方法中删除。之后，您仍然有2个问题。首先是isNotChar由于if语句的缘故将始终为true。您有：if(c != '+' || c != '-' || c != '*' || c != '/' || c != '^')。由于您使用||它始终评估为true，您可能打算将它们全部切换为&&。

您的第二个问题是，您永远不会更新要测试的b1的值。接受新的输入行时，需要在新输入的第一个字符上重新运行isNotChar，并将b1设置为等于该结果。

Answer 2

首先，您必须在main方法之外定义isNotChar（）方法，因为它是静态上下文，并且是在main方法下定义的。

检查输入字符的布尔方法

2 个答案: