英文:
How to avoid error in default condition in the switch statement in the new way Java
问题
以下是已翻译的代码部分：
如何避免在“default”中的 switch 语句中出现错误？此 switch case 根据新标准编写。import java.util.Scanner;public class SwitchCase {public static void main(String[] args) {Scanner scan = new Scanner(System.in);System.out.print("选择选项：");char userChoice = scan.next().charAt(0);switch (userChoice) {case '1' -> System.out.println("1 函数");case '2' -> System.out.println("2 函数");default ->if ((!Character.isDigit(userChoice)) || (userChoice > 3)) { // 此部分会引发下面的错误：System.out.println("输入错误");}}scan.close();}}
一个错误：
Exception in thread "main" java.lang.Error: 未解析的编译问题：语法错误，插入“ThrowExpression ;”以完成 SwitchLabeledThrowStatement语法错误，插入“}”以完成 SwitchBlock在标记“}”上的语法错误，删除此标记at SwitchCase.main(SwitchCase.java:11)
英文:
How do I avoid an error in switch statement in "default"?This switch case is wiritten according to the new standrads.
import java.util.Scanner;public class SwitchCase {public static void main(String[] args) {Scanner scan = new Scanner(System.in);System.out.print("Choose option: ");char userChoice = scan.next().charAt(0);switch (userChoice) {case '1' -> System.out.println("1 funkcja");case '2' -> System.out.println("2 funkcja");default ->if((!Character.isDigit(userChoice))||(userChoice>3)){ #this part throws an error below:System.out.println("Input error");}}scan.close();}}
An error:
Exception in thread "main" java.lang.Error: Unresolved compilation problems:Syntax error, insert "ThrowExpression ;" to complete SwitchLabeledThrowStatementSyntax error, insert "}" to complete SwitchBlockSyntax error on token "}", delete this tokenat SwitchCase.main(SwitchCase.java:11)
答案1
得分: 1
这样检查：
你需要使用冒号（:）来分隔不同的switch case。
我们正在比较的是userChoice，它是一个字符，和3（一个整数）。
public static void main(String[] args) {Scanner scan = new Scanner(System.in);System.out.print("选择选项：");char userChoice = scan.next().charAt(0);switch (userChoice) {case '1': System.out.println("1 函数");case '2': System.out.println("2 函数");default:if (!Character.isDigit(userChoice) || (Integer.parseInt(String.valueOf(userChoice)) > 3)) {System.out.println(userChoice + " 输入错误");}}scan.close();}
英文:
Check this:
You need to use : for switch cases.
We are comparing userChoice which is char to 3(an int).
public static void main(String[] args) {Scanner scan = new Scanner(System.in);System.out.print("Choose option: ");char userChoice = scan.next().charAt(0);switch (userChoice) {case '1': System.out.println("1 funkcja");case '2': System.out.println("2 funkcja");default:if(!Character.isDigit(userChoice)||(Integer.parseInt(String.valueOf(userChoice))>3)){ //#this part throws an error below:System.out.println(userChoice + " Input error");}}scan.close();}
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