using System.Linq;

using System.IO;

using System;

​

​

Console.WriteLine(Drives.GetAllDriveSizeA());

Console.WriteLine(Drives.GetAllDriveSizeB());

Console.WriteLine(Drives.GetAllDriveSizeC());

Console.WriteLine(Drives.GetAllDriveSizeD());

Console.ReadLine();

​

public static class Drives

{

    public static long GetAllDriveSizeA() // With Linq

    {

        return DriveInfo.GetDrives().Where(d => d.IsReady).Sum(d => d.TotalSize / 1024 / 1024 / 1024);

    }

​

    public static long GetAllDriveSizeB()

    {

        long total = 0;

        foreach (DriveInfo drive in DriveInfo.GetDrives()) //With foreach loop

        {

            if (drive.IsReady)

            {

                total += drive.TotalSize / 1024 / 1024 / 1024;

            }

        }

        return total;

    }

​

    public static long GetAllDriveSizeC()//With for loop

    {

        long total = 0;

        var drives = DriveInfo.GetDrives();

        for (int i = 0; i < drives.Length; i++)

        {

            if (drives[i].IsReady)

            {

                total += drives[i].TotalSize / 1024 / 1024 / 1024;

            }

        }

        return total;

    }

​

    public static long GetAllDriveSizeD() //With List<T>.Foreach 

    {

        long total = 0;

        DriveInfo.GetDrives().ToList().ForEach(drive =>

        {

            if (drive.IsReady)

            {

                total += drive.TotalSize / 1024 / 1024 / 1024;

            }

        });

        return total;

    }

}

​