直方图放大问题

Question

我已经解决了编译问题，但我的升迁直方图方法遇到了问题。似乎我的方法的“复制”部分由于某种原因不起作用。有任何想法吗？我会在代码中标记出来。

这是我编写的全部代码。

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

public class Project5
{
    static final int INITIAL_CAPACITY = 10;

public static void main (String[] args) throws Exception
{
    if (args.length < 1) die("You must type the dictionary filename on cmd line.\n");

    // Here we have declared an int array, called 'histogram' with initial capacity of 0
    // it is a freq counter to word lengths in the file 

    int[] histogram = new int[0];

    // Here we have declared an array of String to read the dictionary file into. We use BufferedReader (not Scanner).
    // With each word read in, examine it's length and update word length frequency histogram accordingly

    String[] wordList = new String[INITIAL_CAPACITY];
    int wordCount = 0;
    BufferedReader infile = new BufferedReader( new FileReader(args[0]) );
    while ( infile.ready() ) // i.e. while there are more lines of text in the file
    {
            String word = infile.readLine();

            // YOUR CODE HERE TO CHECK TO SEE IF WORDLIST IS FULL
            // IF SO YOU MUST DO AN UPSIZE JUST LIKE LAB#6
            if ( wordCount == wordList.length ) 
                wordList = upSizeArr( wordList );

            // YOUR CODE HERE to add this word to your list
            String newWord = infile.next(); 
                wordList[wordCount++] = newWord;

            // YOUR CODE HERE TO LOOK AT THE LENGTH OF THE WORD AND UPDATE HISTOGRAM
            int wordLength = word.length;
            if (word.length() > histogram.length)
                histogram = upSizeHisto( histogram, wordLength );

            histogram[word.length()]++;
            // example if word.length() is 5  then histogram[5] gets increment 
            // BUT IF WORD LENGTH IS >= HISTORGRAM LENGTH 
            // THEN YOU NEED TO FIRST CALL upSizeHisto TO UPSIZE THE HISTOGRAM TO BE OF EXACTLY LENGTH word.length()+1 
            // SIMILAR TO HOW YOU HAD TO UPSIZE WORDLIST


    } //END WHILE INFILE READY
    infile.close();

    wordList = trimArr( wordList, wordCount );
    System.out.println( "After trim, wordList length: " + wordList.length );

    // PRINT WORD LENGTH FREQ HISTOGRAM 
    for ( int i = 0; i < histogram.length ; i++ )
        System.out.println("words of length " + i + ": " + histogram[i]);

} // END main


private static void die( String msg )
{
    System.out.println( msg );
    System.exit(0);
}

private static String[] upSizeArr( String[] oldArr )
{
    String[] newArr = new String[oldArr.length * 2];

    for (int cnt = 0; cnt < oldArr.length; cnt++)
    {
        newArr[cnt] = oldArr[cnt];
    }
    return newArr;
}
private static String[] trimArr( String[] oldArr, int count )
{
    String[] newArr = new String[count];

    for (int cnt = 0; cnt < newArr.length; cnt++)
    {
        newArr[cnt] = oldArr[cnt];
    }
    return newArr;
}

private static int[] upSizeHisto( int[] oldArr, int newLength )
{
    int[] newHisto = new int[newLength];
    for (int cnt = 0;  cnt < newHisto.length; cnt++)
    {
        newHisto[cnt] = oldArr[cnt]; // ERROR HERE, Any help guys?
    }
    return newHisto;
}   
} // END CLASS PROJECT#5

我可以使用的最后一点帮助是代码中的最后一个方法。由于错误，我尚未对其进行测试，但如果有任何问题，我可以使用帮助。

谢谢大家。

Answer 1

很少出错。

1.)

  int wordLength = word.length;

到

  int wordLength = word.length();

2.)

String newWord = infile.next();

到

 String newWord = infile.readLine();

3.) 添加 Try Catch

代码如下

public class Project5 {
    static final int INITIAL_CAPACITY = 10;

    public static void main(String[] args) {

        if (args.length < 1)
            die("You must type the dictionary filename on cmd line.\n");

        // Here we have declared an int array, called 'histogram' with initial capacity of 0
        // it is a freq counter to word lengths in the file

        int[] histogram = new int[0];

        // Here we have declared an array of String to read the dictionary file into. We use BufferedReader (not Scanner).
        // With each word read in, examine it's length and update word length frequency histogram accordingly

        String[] wordList = new String[INITIAL_CAPACITY];
        int wordCount = 0;

        try {
            BufferedReader infile = new BufferedReader(new FileReader(args[0]));
            while (infile.ready()) // i.e. while there are more lines of text in the file
            {
                String word = infile.readLine();

                // YOUR CODE HERE TO CHECK TO SEE IF WORDLIST IS FULL
                // IF SO YOU MUST DO AN UPSIZE JUST LIKE LAB#6
                if (wordCount == wordList.length)
                    wordList = upSizeArr(wordList);

                // YOUR CODE HERE to add this word to your list
                String newWord = infile.readLine();
                wordList[wordCount++] = newWord;

                // YOUR CODE HERE TO LOOK AT THE LENGTH OF THE WORD AND UPDATE HISTOGRAM
                int wordLength = word.length();
                if (word.length() > histogram.length)
                    histogram = upSizeHisto(histogram, wordLength);

                histogram[word.length()]++;
                // example if word.length() is 5 then histogram[5] gets increment
                // BUT IF WORD LENGTH IS >= HISTORGRAM LENGTH
                // THEN YOU NEED TO FIRST CALL upSizeHisto TO UPSIZE THE HISTOGRAM TO BE OF EXACTLY LENGTH word.length()+1
                // SIMILAR TO HOW YOU HAD TO UPSIZE WORDLIST
                infile.close();
            } // END WHILE INFILE READY
        } catch (Exception e) {

        }
        wordList = trimArr(wordList, wordCount);
        System.out.println("After trim, wordList length: " + wordList.length);

        // PRINT WORD LENGTH FREQ HISTOGRAM
        for (int i = 0 ; i < histogram.length ; i++)
            System.out.println("words of length " + i + ": " + histogram[i]);

    } // END main

    private static void die(String msg) {
        System.out.println(msg);
        System.exit(0);
    }

    private static String[] upSizeArr(String[] oldArr) {
        String[] newArr = new String[oldArr.length * 2];

        for (int cnt = 0 ; cnt < oldArr.length ; cnt++) {
            newArr[cnt] = oldArr[cnt];
        }
        return newArr;
    }

    private static String[] trimArr(String[] oldArr, int count) {
        String[] newArr = new String[count];

        for (int cnt = 0 ; cnt < newArr.length ; cnt++) {
            newArr[cnt] = oldArr[cnt];
        }
        return newArr;
    }

    private static int[] upSizeHisto(int[] oldArr, int newLength) {
        int[] newHisto = new int[newLength];
        for (int cnt = 0 ; cnt < newHisto.length ; cnt++) {
            newHisto[cnt] = oldArr[cnt];
        }
        return newHisto;
    }
}