Question

因此，对于作业，我必须从文件中读取输入然后输出它。文件中的信息采用以下格式：1行带有股票代码，下一行带有买入数量。例如我们使用的文件：

.ab
15
mox
16
.fy
8
mixe
34

然后我必须输出每个符号的计数和总价。但不知何故，当我运行它时，它只读取前3组数据 - 本例中只有3行数据而不是4行。例如。输出将是：

Enter filename ... lab5data.txt
00000 54.05
00002 Symbol mox does not exist
00003 10.70
00004 Symbol mixe does not exist

我的代码不会输出最后一行“00004符号mixe不存在”

这是我的代码：

import java.util.Scanner;
import java.io.PrintStream;
import type.lib.Stock;
import java.io.File;
import java.text.DecimalFormat;
public class Check05B
{
    public static void main(String[] args) throws java.io.IOException
    {
        Scanner input = new Scanner(System.in);
        PrintStream output = new PrintStream(System.out);
        output.print("Enter filename ... ");
        String fileName = input.nextLine();
        Scanner fileInput = new Scanner(new File(fileName));
        double totalValue = 0;
        int count = 00000;
        String symbol = fileInput.next();
        int quantity = fileInput.nextInt();
        while (fileInput.hasNext())
        {
            Stock myStock = new Stock(symbol);
            double total = myStock.getPrice() * quantity;
            String aFormatCounter = new DecimalFormat("00000").format(count);
            if (myStock.getName() == null)
            output.println(aFormatCounter + " Symbol " + symbol + " does not exist!");
            else
            output.printf("%s %.2f%n", aFormatCounter, myStock.getPrice());
            totalValue += total;
            symbol = fileInput.next();
            count++;
            quantity = fileInput.nextInt();
            count++;
        }
        output.printf("Total value = %.2f%n", totalValue);
        fileInput.close();
    }
}

有人可以帮忙吗？我如何让它读取所有行？谢谢！

Answer 1

您需要在循环的顶部读取symbol和quantity。

考虑

    while (fileInput.hasNext())
    {
        String symbol = fileInput.next();
        if (fileInput.hasNextInt () == false) {
            System.err.println ("File Format Error - expecting an int");
            break;
        }    
        int quantity = fileInput.nextInt();
        Stock myStock = new Stock(symbol);
        double total = myStock.getPrice() * quantity;
        String aFormatCounter = new DecimalFormat("00000").format(count);
        if (myStock.getName() == null) {
            output.println(aFormatCounter + " Symbol " + symbol + " does not exist!");
        }
        else {
            output.printf("%s %.2f%n", aFormatCounter, myStock.getPrice());
        }
        totalValue += total;
        count = count + 2;
    }

从文件中读取输入时，文件中的所有行都不是用Java读取的吗？

1 个答案: