get system free disk space in csharp

main.cs
DriveInfo drive = new DriveInfo("C:\\");
long freeSpace = drive.TotalFreeSpace;
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main.cs
public static string FormatBytes(long bytes)
{
    if (bytes < 0) return "-" + FormatBytes(-bytes);
    if (bytes == 0) return "0 B";
    string[] sizes = {"B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"};
    int i = (int)Math.Floor(Math.Log(bytes, 1024));
    decimal value = (decimal)bytes / (decimal)Math.Pow(1024, i);
    return $"{value:F2} {sizes[i]}";
}
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main.cs
Console.WriteLine($"Free space: {FormatBytes(freeSpace)}");
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