Addition of numbers obtained in foreach in C#

Question

With the following code, I will receive the volume of all Windows hard disks separately

        foreach (var drive in DriveInfo.GetDrives())
        {
            int bb = Convert.ToInt32(drive.TotalSize / 1024 / 1024 / 1024);
        }

And this is what returns

100GB 500GB 2300GB

But I want to collect the numbers and hand them over But this is what I want 100GB + 500GB + 2300GB

2900GB

Answer 1

You can test/run this code on https://dotnetfiddle.net/27YcIp

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;
        DriveInfo[] 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;
    }
}


//DriveInfo.GetDrives() - Get Drive list.
//Where(d => d.IsReady) - filters only drives(elements) that are ready otherwise will get exception when trying to get total size.
//Sum(d => d.TotalSize / 1024 / 1024 / 1024) - Sum each element / 1024 / 1024 / 1024

//d => ....  Is lambda expression (anonymous function). d is the parameter of the function and .... is the value returned by this function.

Output my PC

1360
1360
1360
1360

References
Lambda expressions
Linq - Where
Linq - Sum
List.Foreach