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Let's assume I have a string with a simple arithmetic expression (only additions, subtractions, multiplications and parentheses are allowed):
"2 + 5 x 1024 - (32 x 512 - 16 x 14) + 256"
Is there a ready-made function or library to parse the result, as an int, of this expression?
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You're welcome!
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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a hack:
DataTable dtable = new DataTable();
public double? EvalExpr(string expr, string filter = "")
{
dtable.Clear();
object result;
try
{
result = dtable.Compute(expr, filter);
}
catch(Exception ex)
{
throw new InvalidOperationException(ex.Message);
}
if (result == null) return null;
return Convert.ToDouble(result);
}Sample call:
double? result = EvalExpr("((2 + 5) * 1024) - (32 * 512 - 16 * 14) + 256");See: [^]
Note that a nullable 'double is returned here since the other possible numeric types can be safely cast to 'double. Note the use of 'Convert is required: a simple cast will not work !
«Where is the Life we have lost in living? Where is the wisdom we have lost in knowledge? Where is the knowledge we have lost in information?» T. S. Elliot
modified 18-Aug-19 8:29am.
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Lately i have stumbled upon a Library called mXparser which i think can be useful for your cause.It gives you a lot of flexibility, such as variables, functions, constants, operators.You can check it out.
mXparser – Math Expressions Parser for JAVA Android C# .NET/MONO/Xamarin – Mathematical Formula Parser / Evaluator Library | JAVA, Android, .NET/MONO (.NET Framework, .NET Core, .NET Standard, .NET PCL, Xamarin.Android, Xamarin.iOS), Common Language[^]
Hope it was helpful.
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I'm using the 2015 version of visual studio C#.
I was told that the 2017 version was not stable in places but there are some nice features I'd like to use in the 2017 version.
Does anyone know of a any recent releases of visual studio. Hopefully the next release is more stable.
Brian
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Well ... Visual Studio 2019[^]
I skipped 15 and 17 because they were a little flaky in places compared to 13, but 19 seems pretty stable.
Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
AntiTwitter: @DalekDave is now a follower!
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Good to know thanks.
I hope the latest version still supports Windows 8.1
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This What's new in Visual Studio 2019 - Visual Studio[^] shows the difference between the 15, 17 and 19. I didn't like 15 as it was wacky, 17 was a better one, as it is more integrated with Azure and added Angular stuff. If you have access to the 2019 version, then yeah 19 for sure.
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I have been using VS 2017 for the past two years. Never experienced any issues. The updates were frequent and things were dine nicely. Just a week ago, I installed VS 2019. Certain things like cloud development are easier in VS 2019. As backup, I keep pervious version. So, I uninstalled VS 2015.
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Good to know thanks.
I have a feeling that the new version will use more hard disk space on my c drive which has limited space.
Brian
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I am using a laptop that I purchased in 2012 with intel core i5 16 GB Ram and have not experienced any issues with VS 2019 with respect to memory or disk. I think what you are building within the Visual Studio could cause issues, but not necessarily by IDE.
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I have 3 Network adapaters. I neeed the IP address of the primary, so I'm using this:
foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
{
if (ni.NetworkInterfaceType == NetworkInterfaceType.Ethernet)
{
Console.WriteLine(ni.Name);
foreach (UnicastIPAddressInformation ip in ni.GetIPProperties().UnicastAddresses)
{
if (ip.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
{
Console.WriteLine(ip.Address.ToString());
}
}
}
}
The question is, does NetworkInterface.GetAllNetworkInterfaces() return them in the correct order? How do you know which is the primary?
Thanks
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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That doesn't make sense as there's no such thing as a "primary" network adapter.
You can have a machine connected to multiple networks on multiple adapters. Which one is "primary" depends on which network subnet you arbitrarily consider "primary", and which adapater handles that subnet in the routing table.
The routing table also changes when network status changes, such as when you connect a VPN, or pop a laptop in/out of a dock and switch between wireless and wired networks.
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Let me rephrase.
We have some instruments which use their own adapters. I want the IP address of the adapter connected to the LAN, not the IP address of the instruments
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.
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That doesn't make sense either as the only thing that gets and holds the IP address would be the adapter itself, not the device or code running on it.
The application on the device just says "send this data to this host". It's up to the network stack running on the device to figure out how to do that and which network adapter to use, based on the routing table. Once that is determined, it tells the adapter driver to send the data to the target host.
A single machine (or device) can have multiple IP addresses. The assignment of IP addresses stops at the network adapter. The device the adapters are "plugged into" never gets an address.
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Hi,
I am not a C# programer but the "primary" network interface in the Microsoft Windows operating system is determined by the route metric.
If your question is: What is the primary adapter in Microsoft Windows?
Then the answer is: It's the network card that contains the route with the lowest metric. This applies to both ipv4 and ipv6.
Note: This does not mean the network interface is able to route traffic for all subnets... that would depend on the routing table which may be dynamic. The primary adapter is probably meaningless for your needs.
What exactly are you trying to do?
Best Wishes,
-David Delaune
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I used various code combinations for web page reading, but i have this error:
[The remote server returned an error: (403) Forbidden]
My questions:
- I use VS2010. It's because my version of VS is so old, i keep getting this error?
- Is the same problem for newer versions of VS?
- If newer versions have no problem, what can i add to my version?
- Or if it's the code problem, what is the correct code?
This problem appear for SOME websites. But not on all.
this is a sample of code i use:
string urlAddress = "http://somesite.com";
string ReadPage()
{
string page = "";
HttpWebRequest request;
HttpWebResponse response = null;
Stream stream = null;
request = (HttpWebRequest)WebRequest.Create(urlAddress);
request.UserAgent = "Foo";
request.Accept = "*/*";
response = (HttpWebResponse)request.GetResponse();
stream = response.GetResponseStream();
StreamReader sr = new StreamReader(stream, System.Text.Encoding.Default);
page = sr.ReadToEnd();
if (stream != null) stream.Close();
if (response != null) response.Close();
return page;
}
Thank you.
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It has nothing to do with Visual Studio and everything to do with your code, and you're assumptions about what you're doing and the site you're doing it with.
Why you're setting the UserAgent string and the Accept is beyond me. I also have no idea what you're trying to do so it's impossible to tell you what's going on.
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I can't read html web pages because i get this error. Is now clear enough?
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Remote server returned a 403; so it does not allow you to do what it is you want.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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i want to read a page and on this line :
request = (HttpWebRequest)WebRequest.Create(urlAddress);
the compiler stops and gives me this error:
[The remote server returned an error: (403) Forbidden]
but i just remember that i have .NET 4 and
"
in .NET 4.0, TLS 1.2 is not supported, but if you have .NET 4.5 (or above) installed on the system
then you still can opt in for TLS 1.2 even if your application framework doesn’t support it.
"
so i have to find a workaround.
(this is a comment from an old code i had and i just find it now)
- Is there a way to install a newer .NET in my VS2010 ? (the latest .NET that works for VS2019)
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