Question

好。所以这是本学期的最后一个HW作业，我遗漏了该计划的一大部分，因为这是我唯一无法解决的问题。我正在设置我的FileInputStream并使用for循环将值读入数组，就像我过去做的那样没有问题。出于某种原因，我得到了这个例外并且无法解决这个问题。我已经看过围绕这个异常的大量其他线程，但同样，似乎无法弄明白。请停下来。

这是代码，它编译;

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

public class CollinDunn_1_10 {

  // Declare constants
  static final int MAX_EMPLOY = 30;
  static final String TAB = "\t";
  static final String NL = "\n";
  static final double IRA_INVEST = .08;
  static final double FEDERAL_WITH = .18;
  static final double STATE_WITH = .045;
  static final double SAVINGS = .10;

public static void main (String [] args) throws Exception {

  // I/O String references
  final String INPUT = "CollinDunn_1_10_Input.txt";
  final String OUTPUT = "CollinDunn_1_10_Output.txt";

  // Declare variables
  // One-dimensional array for storing employee names
  String [] names = new String [MAX_EMPLOY];

  // Two-dimensional array for storing employee pay data
  // [0] hours worked [1] pay rate [2] gross pay [3] net pay
  // [4] savings amount [5] IRA amount [6] taxs withheld 
  double [][] payInfo = new double [MAX_EMPLOY][6];

  // Set up I/O
  FileInputStream inputDataFile = new FileInputStream(INPUT);
  Scanner inputFile  = new Scanner(inputDataFile);    
  FileWriter outputDataFile = new FileWriter(OUTPUT);
  PrintWriter outputFile = new PrintWriter(outputDataFile);

  // Read data from the file
  readData(inputFile, payInfo, names);

  // Test printing to see if values are stored - REMOVE 
  for (int i = 0; i < MAX_EMPLOY; i++) {
     System.out.print(names[i] + TAB + payInfo[i][0] + TAB + payInfo[i][1]);
  }

} // End main

 // Method for reading file data into the file.
 // Data is sorted as (number of hours) (pay rate) (name)
 public static void readData (Scanner inputFile, double [][] payInfo, String [] names) {
     for (int i = 0; i < MAX_EMPLOY; i++) {
        payInfo [i][0] = inputFile.nextDouble();
        payInfo [i][1] = inputFile.nextDouble();
        names [i] = inputFile.nextLine();
     } // End For
  return;
} // End readData
} // End Class

*文本文件中的字段如下：（小时）（付费）（姓名）

50.00 10.60 Light Karen L
52.00 10.80 Fagan Bert Todd
62.00 12.24 Antrim Forrest N *

The Exception and stack trace:
Exception in thread "main" java.util.NoSuchElementException

at java.util.Scanner.throwFor(Scanner.java:862)

at java.util.Scanner.next(Scanner.java:1485)

at java.util.Scanner.nextDouble(Scanner.java:2413)

at CollinDunn_1_10.readData(CollinDunn_1_10.java:56)

at CollinDunn_1_10.main(CollinDunn_1_10.java:42)

Answer 1

在尝试检索之前，您永远不会检查是否有要检索的值（查找Scanner.hasNextDouble）。由于for循环经历了MAX_EMPLOY迭代，因此只要输入文件包含少于MAX_EMPLOY的数据行，就会发生此异常。

Answer 2

您应该每次检查您的表格或文件是否包含正确数量的元素，或者它们是否很大。代码应如下所示：

    <?php
function offer($items, $buyItems, $get) {
$offerType = $buyItems+1;
$x = $items;
rsort($x);
$y = count($x);

for($i=$y; $i> 0; $i -= $offerType ) {
        $index = $i-1;


        array_splice($x, $index, 1);
    }


$arrlength = count($x);

for($z = 0; $z < $arrlength; $z++) 
{
    echo $x[$z];
    echo "\n";

}
echo "Total = " . array_sum($x) . "\n";
}
offer(array(2, 5, 7,16, 6, 8, 40, 90), 2, 1);
?>

你不需要“回归”;在这种方法的最后因为这种方法没有任何回报。这是“无效”的方法。

尝试从文件到数组

2 个答案: