histogramProject

import java.util.*;
import java.io.*;
public class FunWithHistograms {
    public static String txtFile = "";
    public static void main(String[] args) throws FileNotFoundException{
        //Intialization
        Scanner console = new Scanner(System.in);
        String answer = "yes";

        //Method Calls
        introMessage();
        while(answer.equalsIgnoreCase("yes")){
            int[] data = readData(console);
            System.out.print("Output file name? ");
            String txtFileOut = console.next();
            PrintStream histogramFile = new PrintStream(txtFileOut);
            System.out.println();
            meanData(data);
            findMaxIndex(data);
            int[] counter2 = getCounts(data);
            histogramFile.println("Histogram for " + txtFile);
            histogramFile.println();
            printHistogram(data, histogramFile);
            summaryStats(data, counter2, histogramFile);
            System.out.println("Histogram Created!");
            System.out.print("Do you want to create another histogram? ");
            answer = console.next();
            if(answer.equalsIgnoreCase("yes")) {
                System.out.println();
            }
        } // end of while loop
        System.out.println();
        System.out.println("Thanks for having fun with histograms!");
    } // end of main method

    //This method prints out a series of strings to inform the user of the program's intent
    //Parameters: none
    //Returns: none
    public static void introMessage(){
        System.out.println("The program will analyze data from a dataset of");
        System.out.println("non-negative integer values. It will produce a");
        System.out.println("histogram of the data and some statistics.");
        System.out.println("The result will be written to an output file.");
        System.out.println();
    } // end of introMessage method

    //This method takes user input to ultimately create an array (based on a file)
    //Parameters: Scanner console (for user input)
    //Returns: int[] fileArray (the array of the user's chosen file)
    public static int [] readData(Scanner console) throws FileNotFoundException{
        System.out.print("Input file name? ");
        txtFile = console.next();

        File fileTxt = new File(txtFile);
        Scanner fileScan = new Scanner(fileTxt);

        int arrayNum = fileScan.nextInt();
        int[] fileArray = new int[arrayNum];

        for(int i = 0; i < fileArray.length; i++){
            fileArray[i] = fileScan.nextInt();
        }

        return fileArray;
    } // end of readData method

    //This method finds the maximum index value of a given array
    //Parameters: int [] data (any given array)
    //Returns: int maxVal (the int that corresponds with the index number)
    public static int findMaxIndex(int[] data) {
        int maxVal = 0;
        for(int i = 0; i < data.length; i++){ // runs for the whole dataset
            if(data[i] > data[maxVal]){ //checks the index via []
                maxVal = i; //updates maxVal into the i index
            }
        }
        return maxVal;
    } // end of findMaxIndex method

    //This method count the occurrences of every value in an array & arranges them based on index
    //Parameters: int [] data (any given array)
    //Returns: int[] counter (an array that stores the counts of all the values)
    public static int[] getCounts(int[] data) {
        int index = data[0]; // gets us at index 0
        for(int i = 0; i < data.length; i++){
            if(index < data[i]){
                index = data[i]; // starts storing the value
            }
        }
        //needs to return a new array
        //array creation
        int[] counter = new int[index + 1]; // has to b. e +1 because index is [0]
        for(int i = 0; i < data.length; i++){
            counter[data[i]]++;
        }
        return counter;
    }

    //This method computes the average of the data in the array
    //Parameters: int[] arr (the array of the data from the file)
    //Returns: double mean (the average of the data set)
    public static double meanData(int[] arr){
        int sum = 0;
        for(int i = 0; i < arr.length; i++){
            sum += arr[i];
        }
        double mean = sum / (double) arr.length;

        return mean;
    } // end of meanData method

    //This method creates the histogram into the output file the user enters
    /*Parameters: int[] data (array of the file's data),
                  PrintStream histogramFile (prints to user's file)*/
    //Returns: none
    public static void printHistogram(int[] data, PrintStream histogramFile){
        int[] counter2 = getCounts(data);

        for (int i = 0; i < counter2.length; i++){
            histogramFile.print(i + "| ");
            for(int j = 0; j < counter2[i]; j++){ // needs to go along with the occurences
                histogramFile.print("*");
            } // end of inner for loop
            histogramFile.println();
        }
        histogramFile.println();
    } // end of printHistogram method

    //This method prints out the primary statistics of the data set into the user's output file
    /*Parameters: int[] data (array of the file's data),
                  int[] counts (array made in getCounts method),
                  PrintStream histogramFile (prints to user's file)*/
    //Returns: none
    public static void summaryStats(int[] data, int[] counts, PrintStream histogramFile){
        //Num Values printing
        int arrayNum2 = data.length;
        histogramFile.println("Num. Values: " + arrayNum2);
        //Mean printing
        double meanData2 = meanData(data);
        histogramFile.println("Mean: " + meanData2);
        //Mode printing
        int mode = findMaxIndex(counts);
        histogramFile.println("Mode: " + mode);
    } // end of summaryStats method

} // end of public class