//********************************
// Program Name: histogram.java  *
// Author: Pat Moss              *
// Date: Nov 11, 2005  Rev: 01   *
//                               *
// Demonstrate a histogram.class *
//********************************

import java.util.Scanner;
import java.io.*;
import javax.swing.*;

public class histogram
{
 public static void main (String[] args) throws IOException
 {
  System.out.println ("histogram.java  by Pat Moss  Rev. 01 11-11-2005");
  System.out.println ("");

  // prompt the user to enter the input data text file name
  // the format is: one integer value per line
  // with each integer value in the range 1 to 100

  JFileChooser chooser = new JFileChooser();
  int status = chooser.showOpenDialog (null);

  if (status != JFileChooser.APPROVE_OPTION)
     System.out.println ("No File Chosen");
  else
  {
   File file = chooser.getSelectedFile();
   Scanner scan = new Scanner (file);

   final int VALUEMIN = 1;   // minumum valid data integer value
   final int VALUEMAX = 100; // maximum valid data integer value
 
   final int RANGEMIN = 1;   // minimum valid range integer value
   final int RANGEMAX = 10;  // maximum valid range integer value
 
   int ary1[] = new int[VALUEMAX+1];
   int len1 = ary1.length;   // get length of the input data array
 
   int ary2[] = new int[RANGEMAX+1];
   int len2 = ary2.length;   // get length of the output data array

   // Initialize the integer array variables
   int i=0;
   for (i=0; i<len1; i++) { ary1[i] = 0; }
   for (i=0; i<len2; i++) { ary2[i] = 0; }

   // entrance to process the input data text file values
   // and then display the histogram values

   // accumulate input data text file values into array ary1[]

  while (scan.hasNext())
  {
   int inpvalue = scan.nextInt();
   // System.out.println ("Value: " + inpvalue);
  
   // if the input data value is in the range 1 to 100
   // then add its occurrence into the frequency array ary1
   if ((inpvalue >= VALUEMIN) && (inpvalue <= VALUEMAX))
   {
    ary1[inpvalue]++;
   }
  }

  // condense the frequency array ary1 (range 1 to 100)
  // into the histogram array ary2     (range 1 to 10)
  for (int k=VALUEMIN; k<len1; k++)  // for #1
  {
   int datavalue = ary1[k];
   int compressedrange = (k - 1) / 10 + 1;

   // System.out.println (datavalue + " " + compressedrange);
  
   if ((compressedrange >= RANGEMIN) 
    && (compressedrange <= RANGEMAX))  // if/else #1
   {
    ary2[compressedrange] += datavalue;
   } else {
    System.out.println ("*Error: item " + k + " : " + datavalue);
   } // if/else #1
  }  // for #1
  
  // Print the results as asterisks per line in a histogram format
  
  for (int m = RANGEMIN; m <= RANGEMAX; m++)  // for #2
  {
   int mmin = (m - 1) * 10 + 1;
   int mmax = (m - 1) * 10 + 10;

   if (mmax < 11) System.out.print (" ");
   if (mmax < 100) System.out.print (" ");

   System.out.print (mmin + " - " + mmax + " | ");
  
   for (int n=1; n <= ary2[m]; n++) // for #3
   {
    System.out.print ("*");
   } // for #3
    System.out.println("");
  }  // for #2
  
  System.out.println ("");
  System.out.println ("All Done...");
  }
 }
}