C# Output max min average array using a text file?

Question

I had done a previous exercise whereby I had to write a program where a user would input 30 different numbers (hours) and the program would spit out the array, average, min, and max. That was fine. Now, however, I am tasked with reading the numbers from a text file (and outputting the same as before - array, avg, min, max).

I am hitting an error based on the original exercise, where I am told that a name does not exist in the program (I understand this is because the text doc now holds that previous name). I don't know what I need to do to change this.

I've watched some videos and found similar problems listed on this site but am stuck :(. Can anyone help?

Program code is:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace IntsArray
{
    class Program
    {
        static void Main(string[] args)
        {

            StreamReader myReader = new StreamReader("Values.txt");
            string line = "";

            while (line != null)
            {
                line = myReader.ReadLine();
                if (line != null)
                    Console.WriteLine(line);
            }
            myReader.Close();
            Console.ReadLine();

            for (int index = 0; index < hoursArray.Length; index++)
            {
                Console.Write("Enter your hours: ");
                hoursArray[index] = int.Parse(Console.ReadLine());
            }
            Console.WriteLine("Numbers in the list: " + hoursArray.Length);
            for (int index = 0; index < hoursArray.Length; index++)
            {
                Console.WriteLine(hoursArray[index]);
            }
            Console.ReadKey();

            int total = 0;      
            double average = 0; 
            for (int index = 0; index < hoursArray.Length; index++)
            {
                total = total + hoursArray[index];
            }

            average = (double)total / hoursArray.Length;
            Console.WriteLine("Average = " + average.ToString("N2"));


            int high = hoursArray[0]; 

            for (int index = 1; index < hoursArray.Length; index++)
            {
                if (hoursArray[index] > high)
                {
                    high = hoursArray[index];
                }
            }

            Console.WriteLine("Highest number = " + high);


            int low = hoursArray[0];   

            for (int index = 0; index < hoursArray.Length; index++)
            {
                if (hoursArray[index] < low)
                {
                    low = hoursArray[index];
                }
            }

            Console.WriteLine("Lowest number = " + low);
            Console.ReadKey();

        }
    }
}

The numbers in the Values.txt looks like this:

8
24
9
7
6
12
10
11
23
1
2
9
8
8
9
7
9
15
6
1
7
6
12
10
11
23
1
2
9
8

I understand the problem, I just do not know how to fix it!

Answer 1

You need to define the array

int[] hoursArray = new int[WHATEVER LENGTH IT SHOULD BE];

then your StreamReader read line thing has to look something like this:

string line = "";
int position = 0; //needed to set the array position
while (line != null)
{
    line = myReader.ReadLine();
    if (line != null)
    {
        Console.WriteLine(line);
        hoursArray[position] = int.Parse(line); //convert line to int and sotres it in the array
        position++;
    }
}

if you want to make it more flexible i would use a list instead of an array

Edit: min max avg calulation:

int max = 0;
int min = 9999999;
double avg = 0;

for (int i = 0; i < hoursArray.Length; i++)
{
    if (hoursArray[i] > max) //if there is a higher value then the current max
        max = hoursArray[i];

    if (hoursArray[i] < min) //if there is a lower value then the current min
        min = hoursArray[i];

    avg = avg + hoursArray[i];
}
avg = avg / hoursArray.Length;

Console.WriteLine("Max: " + max);
Console.WriteLine("Min: " + min);
Console.WriteLine("Avg: " + avg);
Console.ReadLine();

You just need to put them together in you main and there you have it

Answer 2

First thing you will do is to identify the number of lines in the textfile.

var file = new StreamReader("file.txt").ReadToEnd(); 
var lines = file.Split(new char[] {'\n'});  
var count = lines.Count;

Based on this count initialize your array

int[] hoursArray = new int[count];

After that populate your array.

int index = 0;
while ((line = sr.ReadLine()) != null) 
{
    hoursArray[index++] = Convert.ToInt32(line);
}

Then last step, you can now apply linq to get max min and avg same as what arvin said.

var max = hoursArray.Max();
var min = hoursArray.Min();
var avg = hoursArray.Avg();

Answer 3

If you want to read numbers from a file, why do you have this code ?

for (int index = 0; index < hoursArray.Length; index++)
{
    Console.Write("Enter your hours: ");
    hoursArray[index] = int.Parse(Console.ReadLine());
}

what you can do is read the numbers from a file, store it in Array or List and then use Linq to get Max, Min and Average.

List<int> Numbers = System.IO.File.ReadAllLines("Your File Path")
                   .Select(N=> Convert.ToInt32(N)).ToList();

Console.WriteLine(Numbers.Average());
Console.WriteLine(Numbers.Max());
Console.WriteLine(Numbers.Min());