Find the name of the student with the top mark, display their name and mark

Normally you should use a CSV library to read CSV, but assuming your data is simple, a Split should be adequate. Using the File.ReadLines() method allows you to read the file as an IEnumerable<string> which you can then process with LINQ:

var ans = File.ReadLines("TestData.csv")
              .Skip(1) ' skip header line
              .Select(line => line.Split(',')) ' break lines into fields
              .MaxBy(parts => Int32.Parse(parts[2])); ' find line with maximum score

posted about 1 year ago

CC BY-SA 4.0

NetMage‭

21 reputation 0 1 2 0

That's nice that you're provided your attempts but, as it was already mentioned in comments, it would be better to show us all the parts. Again, if you're not sure how to write it properly in C# that's fine - just show us some pseudo-code and we help you from there.

Anyway, this is a simple task to find the maximum value among some sequence of data.

The most obvious algorithm would be:

1. Pick some initial value (*) as a "local" maximum.
2. Read a value.
3. Compare a local maximum with the current value.
4. Assign the biggest one from these two as a local maximum.
5. Repeat step 2 - 4 until the whole sequence is over.

[*] You can take the first value in a sequence as an initial.

First step is done, now it's time to actually write some code.

Let's start with creating a class that represents data in the file. This isn't necessary step for this task but I still suggest you to use it since it might be useful in the future:

public class Student
{
    public Student(string name, string surname, uint score)
    {
        Name = name;
        Surname = surname;
        Score = score;
    }

    public string Name { get; }

    public string Surname { get; }

    public uint Score { get; }

    public override string ToString() =>
        $"{Name} {Surname} [{Score}]";
}

Now, when data is described, we can parse it and do something with it. Using LINQ is probably easiest way:

const string filepath = "TestData.csv";

var bestStudent =
    File.ReadLines(filepath) 
        .Skip(1) // skip header
        .Aggregate<string, Student>(null, (acc, line) =>
        {
            var fields = line.Split(',', StringSplitOptions.RemoveEmptyEntries);
            var student = new Student(fields[0], fields[1], uint.Parse(fields[2]));
            if (acc is null || acc.Score < student.Score)
            {
                return student;
            }

            return acc;
        });

if (bestStudent is null)
{
    Console.WriteLine("Input file is empty");
}
else
{
    Console.WriteLine("Student with a highest mark:");
    Console.WriteLine(bestStudent);
}

I didn't write code that validate input (which you should do) since it's unrelated to this task. As well as I used only , symbol as a separator to parse a line. I'd suggest considering using some library to parse .csv file.

posted over 3 years ago

CC BY-SA 4.0

FoggyFinder‭

318 reputation 2 12 33 7