How to find the mean, median, mode, and range from an input file?

Question

I need to find the mean, median, mode, and range from an input file.

[input file has the numbers{60,75,53,49,92,71}]

I don't know how to print the calculations from the range out or calculate the mode.

It's pretty bad, I'm very new to Java.

It would be great if anyone could help me with it.

import java.io.*;
import java.util.*;

public class grades {

    public static double avg(double[] num) {
        double total = 0;
        int j = 0;
        for (; j < num.length; j++) {
            total += num[j];
        }
        return (total / j);
    }

    public double getRange(double[] numberList) {
        double initMin = numberList[0];
        double initMax = numberList[0];
        for (int i = 1; i <= numberList.length; i++) {
            if (numberList[i] < initMin) initMin = numberList[i];
            if (numberList[i] > initMax) initMax = numberList[i];
            double range = initMax - initMin;

        }
        return range;
    }

    public static void main(String[] args) throws IOException {
        double[] num = new double[12];
        File inFile = new File("data.txt");
        Scanner in = new Scanner(inFile);
        for (int i = 0; i < num.length && in.hasNext(); i++) {
            num[i] = in.nextDouble();
            // System.out.println(num[i]); 
        }

        double avg = grades.avg(num);
        System.out.println("Arithmetic Mean = " + avg);
        System.out.printf("Median = %.2f%n", grades.getMedian(num));
        System.out.println("Range = " + range);


    }

    public static double getMedian(double[] num) {
        int pos = (int) num.length / 2;
        return num[pos];
    } 

}

Answer 1

I don't know how to print the calculations from the range out or calculate the mode.

You have already written a function to calculate the Range. Here is how you can print the Range.

System.out.println("Range = " + getRange(num));

Here is a quick code snippet to calculate the Mode:

public static double calculateMode(final double[] numberList) {
    double[] cnts = new double[numberList.length];
    double mode = 0, max = 0;

    for (int i = 0; i < numberList.length; i++) {
        /* Update Count Counter */
        cnts[numberList[i]]++;
        /* Check */
        if (max < cnts[numberList[i]]) {
            /* Update Max */
            max = cnts[numberList[i]];
            /* Update Mode */
            mode = numberList[i];
        }
    }
    /* Return Result */
    return mode;
}