Java Homework Five
Histogram 2.0

The purpose of this assignment is to convert your histogram code into a histogram class. You will also add a new feature to your graphing.

Take your existing code and divide it into two files. One file will contain the histogram class and the other will contain your main() that tests the new class.

The histogram class should contain at least three methods:

constructor histogram(int)

public method add_value(int)

public method write()

Add_value is passed an integer data value that is to be graphed later. So, if someone wants to plot 50 data values, their code will call add_value 50 times.

The write method just prints the graph.

Add a new feature to your new class. Allow the user to change the grouping size of the bars. In other words, instead of always having bars represent the values 0-9, 10-19, etc., allow the user of your class to change the grouping to 0-19, 20-39, etc. To do this, add a public integer field named "grouping". The default grouping size should be 10. (Note: implement this feature last.)

The main() will do the same things as the previous assignment : ask for a filename, read the filename, open the file, read the values, etc. The difference in the main() for this assignment is that it will declare a variable of type "histogram". Instead of adding the values from the file into an array, add them into the histogram.

Here are bits of code out of my main():

      int linecount;   // num of lines in files = max num of data values
     ...
     
     // create a graph instance
     histogram myHistogram;
     myHistogram = new histogram (linecount);

     // read the lines of the file
     for (int i=0; i<linecount; i++)
        try
        {
          nextvalue = Integer.parseInt(inputFile.readLine());
          myHistogram.add_value(nextvalue);
        }
        catch (Exception e)
        {
        }
     inputFile.close();
     System.out.println ("Done reading from file");

     // output the histogram twice
     System.out.println ("Histogram One - grouping = 10");
     myHistogram.write();
     System.out.println ("Histogram Two - grouping = 20");
     myHistogram.grouping = 20;
     myHistogram.write();

To make grading a bit easier, please name the class (and hence the file name) that contains main() "hw05_test". Obviously, the code for your histogram class must go in a file named "histogram.java".

Email your two files (histogram.java and hw05_test.java) to dannellys@winthrop.edu with the subject "CSCI 392 HW05". Please send these two files as attachments.