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I have made an exercise where I need to calculate the average per row of a .txt file. (see below)

Toa Narumi gradeA 10 8 7 4 6,5
Jean-François Le Clerk gradeB 5 4 7
Joe GradeC 10 10

I only want the numbers behind the name and grade. This is my code:

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

namespace RenoD_Oef_Strings
{
    class Program
    {
        static void Main(string[] args)
        {
            // Variablen
            StreamReader bestand = new StreamReader(@"F:\RenoD_Oef_Strings\Punten.txt");
            string strRow; // String used to read every row of .txt file
            double?[] dblPoints; // Double array used to store all values
            List<string> strInput = new List<string>(); // String List used to store all data from .txt


            // Code
            while ((strRow = bestand.ReadLine()) != null) // Read row per row in .txt
            {
                strInput = strRow.Split(' ').ToList(); // Puts every word in the row in to the list

                int intX = 0;
                foreach(string strX in strInput)    // Calculate how many strings are in the list
                {
                    intX++;
                }

                dblPoints = new double?[intX];  // Calculate the max number of elements the double array can have

                intX = 0;
                foreach(var x in strInput)  // Checks if elements in the list can be converted in to a double 
                {
                    try
                    {
                        double dblR = Convert.ToDouble(x);  // If element can be converted in to a double, it will be stored in the double array

                        dblPoints[intX] = dblR;
                        intX++;
                    }
                    catch
                    {
                        intX++; // If element CAN NOT be converted in to a double, it will be still be stored in the double array but without any value
                    }
                }

                double dblAverage = 0;   // Double used to save the total average of one row
                intX = 0;
                foreach(var k in dblPoints)
                {
                    if (k.HasValue) // Elements without value will be ignored
                    {
                        dblAverage += Convert.ToDouble(k); // All double values will be added up
                        intX++; // Used to see how much double values there are to calculate average
                    }
                }

                dblAverage = Math.Round(dblAverage/intX, 2);  // Calculate average + round up to two decimals

                Console.WriteLine(dblAverage.ToString());
            }

            bestand.Close();

            Console.ReadKey(); 
        }
    }
}

What I have done is

  • Read row per row .txt file

  • Put all elements of that row in a list

  • Calculate how many elements that the double array will need to store (same number of elements the list has), which I later on use to store all doubles of the list

  • Check if elements in the list can be converted in to a double array; If the element can be converted in to a double, it will be stored in the double array.

If element CAN NOT be converted in to a double, it will be still be stored in the double array but without any value.

  • Only calculate the average of the elements in my double array that have values.

I have tested the code, and it works without any issue.

My question is, have I taken a good approach? What would you have done to make it more efficient?

I have tried searching in other threads for solutions. I have seen simular questions, but was unable to find any exactly the same as my exercise.

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migrated from stackoverflow.com May 5 at 15:23

This question came from our site for professional and enthusiast programmers.

  • \$\begingroup\$ Some tips: Dont mix german and english words. You use an object oriented language: Try to structure your code in functions. Then try to structure your code in classes. Dont mention the type of a variable in its name. This is old fashioned style. Dont write unnecessary code - use the appropriate methods of your language. If you explicitly want to implement already implemented features by yourself - use the "reinventing-the-wheel"-tag. Good luck and a lot of fun! \$\endgroup\$ – Dexter Thorn May 5 at 15:57
2
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  • Enclose the file reading in a using statement
  • Use double.TryParse or regex to parse the numbers
  • Use Linq extention method Average() to calculate average
  • The size of strInput is strInput.Count, no need for a loop

Hear is a simpler code:

using (StreamReader bestand = new StreamReader(@"F:\RenoD_Oef_Strings\Punten.txt"))
{
    string strRow; // String used to read every row of .txt file
                    // Code
    while ((strRow = bestand.ReadLine()) != null) // Read row per row in .txt
    {
        List<string> strInput = strRow.Split(' ').ToList(); // String List used to store all data from .txt
        List<double> dblPoints = new List<double>(); // Double list used to store all values

        foreach (var x in strInput)  // Checks if elements in the list can be converted in to a double 
        {
            if (double.TryParse(x, out double result))
            {
                dblPoints.Add(result);
            }
        }
        double dblAverage = dblPoints.Average();

        Console.WriteLine(dblAverage.ToString());
    }
}

Console.ReadKey();
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  • \$\begingroup\$ Thank you for your reply! It is indeed way simpeler. \$\endgroup\$ – Toa Narumi May 5 at 13:11
  • \$\begingroup\$ Clean and does the trick. There is theoretical edge case where a grade could be NaN, which passes the TryParse check but the average would also be a NaN. If this could be a possibility, it would need to be accounted for. \$\endgroup\$ – Rick Davin May 6 at 16:11

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