java - 使用数组调用方法时出现“.class”预期错误

Question

这个问题已经有答案了:

What does "error: '.class' expected" mean and how do I fix it (1 个回答)

已关闭 3 年前。

到目前为止，我已经买了三本书并观看了几个视频，但我仍然不清楚为什么它不能编译。任何帮助将不胜感激。我正在尝试读取信用卡号码文件，并根据用户在主文件中输入的号码进行检查。这是我的类(class)，然后是我的主要类(class):(感谢您的帮助)

    import java.util.Scanner;
    import java.io.*;

    public class Validator1
    {
        int[] valid;    

    public Validator1()throws IOException
    {   

    }

    public Validator1(String fileName)throws IOException
    {   
        int beginning = 0;
        int place = 0;
        int size = 0;

        File file = new File(fileName);
        Scanner inputFile = new Scanner(file);
        Scanner inputFile2 = new Scanner(file);

        while(inputFile.hasNextInt())
        {
            size++;
            inputFile2.nextInt();
        }


        while(inputFile2.hasNextInt() && place < valid.length)
        {
            valid[place] = inputFile2.nextInt();
            place++;
        }

    }

    public void sort(int[]valid)
    {
        valid = new int[valid.length];
        for(int start = 0; start < valid.length; start++)
        {
            int lowestValue = valid[start];
            int lowestIndex = start;
            for(int i = start + 1; i < valid.length; i++)
            {
                if(valid[i] < lowestValue)
                {
                lowestValue = valid[i];
                lowestIndex = i;
                }
            }
            int temp = valid[start];
            valid[start] = valid[lowestIndex];
            valid[lowestIndex] = temp;
        } 
    }

    public boolean isValid(int[] valid, int number)
    {
        int low =0;
        int high = valid.length-1;
        while(high >= low)
        {
            int middle = (high + low)/2;
            if(valid[middle] == number)
            {
                return true;
            }
            if (valid[middle] < number)
            {
                low = middle +1;
            }
            if(valid[middle] > number)
            {
                high = middle-1;
            }
        }
        return false;
    }
}




import java.util.Scanner;
import java.io.*;

public class ChargeIt1
{
    public static void main(String[] args)
    {
        int accountNumber;
        int[] valid = 0;
        Scanner keyboard = new Scanner(System.in);



        System.out.println("Enter the file name: ");
        String fileName1 = keyboard.nextLine();
        String fileName = fileName1 + ".txt";

        File file = new File(fileName);

        while(!file.exists())
        {
            System.out.println("the file does not exist");
            System.out.println("Enter the file name: ");
            fileName1 = keyboard.nextLine();
            fileName = fileName1 + ".txt";
            file = new File(fileName);

        }
        System.out.println("Enter your charge account number: ");
        accountNumber = keyboard.nextInt();

        //Validator1 val = new Validator1(fileName);
        try
        {
            Validator1 val = new Validator1(fileName);
            if(val.isValid(valid, accountNumber))
                System.out.println("That is a valid account number.");
            else
                System.out.println("That is an INVALID account number.");

        }
        catch(Exception e)
        {
            //System.out.println("An error has occurred.");
            e.printStackTrace();
        }

    }
}

Answer 1

这一行是错误的:

int[] valid = 0;

0 不是数组。