java - 简单 Java 程序中的意外错误

Question

我正在学习 Java，我想制作一个非常基本的计算器。但看起来我遇到了一个问题!

这是代码:

import java.util.Scanner;

public class apples{
    public static void main(String args[]){
        int test = 6;
        if(test != 9){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
}

所以在 Eclipse 中我尝试运行它，但问题是它不起作用并显示此错误:

Exception in thread "main" java.lang.Error: Unresolved compilation problem:

at apples.main(apples.java:4)

Answer 1

倒数第二个括号有一些不可见的字符，您可以看到一个红点(非常细)，如果删除相同的字符，您的程序就完全没问题。

包含特殊字符的错误代码

import java.util.Scanner;

    public class AdvanceCollection {
     public static void main(String args[]){
                Scanner scan = new Scanner(System.in);
                double fnum, snum, answer;
                System.out.println("Enter first number: ");
                fnum = scan.nextDouble();
                System.out.println("Enter second number: ");
                snum = scan.nextDouble();
                answer = fnum + snum;
                System.out.println(answer);
     }
     }

正确的代码，不存在该问题

import java.util.Scanner;

public class AdvanceCollection {
 public static void main(String args[]){
            Scanner scan = new Scanner(System.in);
            double fnum, snum, answer;
            System.out.println("Enter first number: ");
            fnum = scan.nextDouble();
            System.out.println("Enter second number: ");
            snum = scan.nextDouble();
            answer = fnum + snum;
            System.out.println(answer);
 }
 }