问题

在下面的代码中，在底部，由于某种原因，尽管我赋予了```encodingCharacter = encodeArray[j];```的值。之后我尝试打印出该特定下标的值。但由于某种原因，那个语句引起了问题。在运行程序后，我看到它打印了两行空白，我不知道为什么我不能将字符值```'z'```赋予```encodingCharacter```。


import java.util.Scanner;

public class UserInputDemo1 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        
        System.out.println("Would you like to encode or decode a message.");
        
        System.out.println("If you would like to encode a message enter true. If you would like to decode a message enter false");
        
        System.out.println("Note that blank spaces are separated by a space and the message terminates with a period.");
        
        boolean encodeOrDecode = input.nextBoolean();
            
        if (encodeOrDecode) {
            Scanner scan = new Scanner(System.in);
            
            System.out.println("Please enter the message you would like to be encoded.");
            
            String encodeMessage = scan.nextLine();
            
            char[] encodeCharArray = encodeMessage.toCharArray();
            
            encodeMessage(encodeCharArray);
        }
        
        if (!encodeOrDecode) {
            Scanner scan = new Scanner(System.in);
            
            System.out.println("Please enter the message you would like to be decoded.");
            
            String decodeMessage = scan.nextLine();
            
            char[] decodeCharArray = decodeMessage.toCharArray();
        }
    }
    
    public static void encodeMessage(char encoding[]) {
        char encodeArray[] = new char[encoding.length];
        
        for (int j = 0; j < encoding.length; j++) {
            char encodingCharacter = encoding[j];
            
            if (encodingCharacter == 'a') {
                encodingCharacter = 'z';

                System.out.println(encodingCharacter);
                
                encodingCharacter = encodeArray[j];
                
                System.out.println(encodeArray[j]);
            }
            
            if (encodingCharacter == 'b') {
                encodingCharacter = 'y';

                System.out.println(encodingCharacter);
                
                encodingCharacter = encodeArray[j];
            }
        }
        
        String encodedArray = new String(encodeArray);
        
        System.out.println(encodeArray);
    }
}

import java.util.Scanner;  
public class UserInputDemo1  
{  
public static void main(String[] args)  
{  
Scanner input = new Scanner(System.in);
//creating scanner named input.
System.out.println ("Would you like to encode or decode a message."); 
System.out.println ("If you would like to encode a message enter true. If you would like to decode a message enter false");
System.out.println("Note that blank spaces are seperated by a space and the message terminates with a period.");
boolean encodeOrDecode = input.nextBoolean();
if (encodeOrDecode)
{
Scanner scan = new Scanner(System.in);   
System.out.println("Please enter the message you would like to be encoded.");  
String encodeMessage = scan.nextLine();  
char[] encodeCharArray = encodeMessage.toCharArray();
encodeMessage(encodeCharArray);
}
if (!encodeOrDecode)
{
Scanner scan = new Scanner(System.in); 
System.out.println("Please enter the message you would like to be decoded.");  
String decodeMessage = scan.nextLine();                
char[] decodeCharArray = decodeMessage.toCharArray();
}
}
public static void encodeMessage (char encoding [])
{
char encodeArray [] = new char [encoding.length];
for (int j = 0; j < encoding.length; j++ )
{
char encodingCharacter = encoding[j];
if (encodingCharacter == 'a')
{
encodingCharacter = 'z';
System.out.println(encodingCharacter);
encodingCharacter = encodeArray[j];
System.out.println(encodeArray[j]);
}
if (encodingCharacter == 'b')
{
encodingCharacter = 'y';
System.out.println(encodingCharacter);
encodingCharacter = encodeArray[j];
}
}
String encodedArray = new String(encodeArray);
System.out.println (encodeArray);
}
}

答案1

得分: 0

在第 15 行发生了 java.util.InputMismatchException 异常。

您的 input.nextBoolean() 会返回输入中的下一个标记是否为布尔值，而不是是否有另一个字符。

我相信您在寻找 input.hasNext()，或者类似的内容。

<!-- 这是我的第一个答案！- 2021/4/30 -->