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Thread: Printing a Histogram Help - Arrays

  1. #1
    Junior Member
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    Default 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!
    //************************************************************     
    **/
     
     
    }


  2. #2
    Little Star
    Join Date
    May 2009
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    Default Re: Printing a Histogram Help - Arrays

    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.

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