Thread: Printing a Histogram Help - Arrays

Hello All,

I am currently working on a assignment where we have to input a number of students, generate (either randomly with a gaussean distribution or via user input) a test score of 1-100 for each student, and then print a histogram that represents the scores. The scores are broken down in to ranges of 10 (1-10, 11-20, 21-30, etc.) and for each grade within each range the program prints out an asterix ("*"). I have completed my assignment where it prints out all of the test scores and prints the histogram horizontally (the first row is range 1-10: *****, the second row is range 11-20: **, etc.

Now that my assignment is over I am trying to mess around with the program and figure out how prinit it vertically, so that there will be a row at the bottom of the graph that displays the grade ranges, and the asterixes are printed vertically above each group. Unfortunately, I just cannot figure this out. I would greatly appreciate any help and advice that anyone can give.

Take care and have a great day....

ciao,
john.

Here is my code:

import javax.swing.*;
import java.util.*;
import java.text.*;
 
 
public class assignment6
{
    public static void main (String[] args)
    {
 
        String continueOption;
 
        do
        {
            int n = 1;
            int pupils = 1;
 
            int [] scores = new int [10];
 
           String msg1 = "How many students are there in the class?";
           String msg2 = "Please input a positive number.";
           String msg3 = "Would you like to input numbers from the Console" + 
                "or have the computer Randomly generate for you?" + "\n" +
                "(Enter \"C\" for Console Input or \"R\" for Random Generation)";
           String msg4 = "Would you like to repeat? (Y/N)";
           String msg5 = "Thank you for using this Teaching Aid." + "\n" + 
                "We hope all your students were paying attention and passed." + "\n" + 
                "Have a great summer, Professor Gordon!";
 
 
           do
           {
               pupils = Integer.parseInt(JOptionPane.showInputDialog(msg1));
               if (pupils <= 0)
               {
                   JOptionPane.showMessageDialog(null,msg2);
                }
            }
 
            while (pupils <= 0);
            String choice = JOptionPane.showInputDialog(msg3);
 
            if ((choice.charAt(0)=='C') || (choice.charAt(0)=='c'))
                scores = userNum(pupils);
 
            else
            {
                if(( choice.charAt(0)=='R') || (choice.charAt(0)=='r'))
                    scores = randomNum(pupils);
            }
 
            histogram(scores);
 
            continueOption = JOptionPane.showInputDialog(msg4);
 
            if (continueOption.equals("n") || continueOption.equals("N"))
            {
                JOptionPane.showMessageDialog(null, msg5, "Thank you message",
                    JOptionPane.INFORMATION_MESSAGE);
                System.exit(0);
            }
 
            System.out.println("\n");
 
        }
        while(continueOption.equals("y") || continueOption.equals("Y"));
    }
 
 
 
 
 
 
 
    public static int[] userNum(int n)
    {
        int i, num;
        int [] list = new int [10];
 
        String msg6 = "Please enter the score between 1-100.";
        String msg7 = "The input is wrong, Please enter the score between 1-100.";
 
        System.out.print("Test Scores:");
 
        for (i = 0; i < n; i++)
        {
            num = Integer.parseInt( JOptionPane.showInputDialog(msg6));
 
            if ((num < 1) || (num > 100))
            {
                do
                {
                    num = Integer.parseInt( JOptionPane.showInputDialog(msg7));
                }
 
                while ((num < 1) || (num > 100));
            }
 
            if (i%10 == 0)
                {System.out.println();}
 
            System.out.print(num + "   ");
 
            int value = (((int)num)-1)/10;
 
            list [value]++;
        }
 
        return list;
    }
 
 
 
 
 
 
 
    public static int [] randomNum(int n)
    {
 
        int [] list = new int[10];
 
        Random generator = new Random();
 
        int i; 
        double num = 0;
 
        System.out.print("Test Scores:");
 
        for(i = 0; i < n; i++)
        {
 
            do
            {
                num = generator.nextGaussian();
 
                num *= 15;
                num += 60;
 
 
            }
 
        while ((num < 1) || (num > 100));
 
            int conversion = (int)num;
 
 
            if (i%10 == 0)
                {System.out.println();}
 
            System.out.print( "  " + conversion);
 
            int value = (conversion-1)/10;
 
            list [value]++;
        }
 
        return list;
    }
 
 
 
 
 
 
 
    public static void histogram(int [] scores)
    {
        int i = 0;
        int index;
        double max;
        int result, key;
 
 
        System.out.println("\n" + "\n" + "Histogram:");
 
        for(i = 0; i < 10; i++)
        {
            int asterix = scores[i];
 
            System.out.print(String.format("%2d", ((i*10)+1)) + " - " + 
            String.format("%3d", ((i+1)*10)) + ":  ");
 
            {
                for(int k = 0; k < asterix ; k++)
                System.out.print("*");
            }
 
 
            System.out.println();
 
        }
        System.out.println();
 
/**
//************************************************************
//Finding the largest group of scores 
 
            result = findLargest(scores,0,scores.length);
            System.out.println(result);
            System.out.println(scores[result]);
 
 
//Largest group found!
//************************************************************
**/            
    }
 
 
 
 
 
/**     
//************************************************************
//Finding the largest group of scores 
 
    public static int findLargest(int [ ] list,int start, int n)
    {
        int largest = start;
 
        for(int i = start+1;i<n;++i)
            if (list[i] > list[largest])
                largest = i;
 
       return largest;         
    }
 
//Largest group found!
//************************************************************     
**/
 
 
}

I would suggest to use tab to align them in a nice row.. Another option is to count how big strings are and try to compensate with spaces if string is too short..

using tabs:

/**
 * Haven't tested this code, wrote it from the head,
 * so use it more as a pseudo code than java code
 */
String firstLine = "first Studen \t first score \t first info";
String secondLine = "second Student \t second Score \t second info";

If values differ by length greatly, you might need to insert several tabs.