小编Emm*_*yde的帖子

我正在编写一个程序,它将一系列单词分成标记并读取文本,然后计算它们的频率.此代码有几个相关代码(WordCount,FreqStudy和Echo),但WordFreq类是导致java.lang.NullPointerException错误的原因.这是我的WordFreq代码:

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

public class WordFreq extends Echo{

  WordCount[] wcArray;
  int ct;
  String[] sentence;
  double freq;
  String newLine;

  public WordFreq(String f, String words) throws IOException{
    super(f);
    String[] wordString = words.split(" ");
    for(int i=0; i<wordString.length; i++)
      wcArray[i] = new WordCount(wordString[i]);
    Scanner scan = new Scanner(new FileReader(fileName));
  }

  public void processLine(String line){
    newLine = line.toLowerCase();
    sentence = newLine.split(" "); 
    for(String s: sentence){
      for(WordCount w: wcArray){
        if(w.getWord().equals(s))
          w.incCount();
      }
      ct++;
    }     
  }

  public void reportFrequencies(){
    for (int i=0; i<wcArray.length; i++){
      freq …