convert signed int to unsigned int

Posted on 2006-06-28
Last Modified: 2010-08-05
Hey Experts,
How do I convert a number represented as a string from a text box to unsigned. For example, the number in the text box is -492961707.
Question by:freename
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 25

Expert Comment

ID: 17004924
Do you want to convert it to 492961707 or the unsigned equivalent (base-2 inverse)?
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 17004931

int n = int.Parse(textbox.text)
uint u = unchecked(n < 0 ? -n : n);
LVL 25

Expert Comment

ID: 17004994
Depending on if you want the 32-bit equivalent or 64-bit equivalent,

            Int64 i = -492961707;
            String s = i.ToString("x");
            u = UInt64.Parse(s, System.Globalization.NumberStyles.AllowHexSpecifier);


            Int32 i = -492961707;
            String s = i.ToString("x");
            u = UInt32.Parse(s, System.Globalization.NumberStyles.AllowHexSpecifier);
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

LVL 25

Expert Comment

ID: 17005014

Very slick!  But wouldn't it just be

int n = int.Parse(textbox.text)
uint u = (uint)unchecked(n);
LVL 37

Expert Comment

ID: 17007835
dstanley don't be too impressed it is googled :) from

Generally one should use Math.Abs ... there is 1 number it will fail for -2147483648 (due to overflow) which is why the unchecked solution posted is mentioned ... if this one number doesn't matter to you then it is a much cleaner answer and does a better job expressing what you are trying to do.

int n = int.Parse(textbox.text)
uint foo = (uint) math.abs(value)


LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 17007878
>don't be too impressed it is googled
I admit to be culprit on that point :-)

Author Comment

ID: 17008738
I see some very good solutions here. But I don't think I was clear enough on my original request. My apologies. From what I understand (I'm getting this information second hand),  the number originates on a system that uses unsigned numbers. Then it is delivered (the means is unimportant) to a system that has signed numbers. Therefore, when represented on the new system, the negative sign may be present, as in this case, because the signed bit is set. I would like to know what the original number was on the system the uses unsigned numbers. Is this possible?
LVL 25

Accepted Solution

dstanley9 earned 100 total points
ID: 17009439
It depends on how many bits were used to represent the number on the original system.  The negation of an unsigned int will be different for each:

uint ui = (uint)unchecked(i);  // returns 3802005589 (0xe29e0055)
ulong ul = (ulong)unchecked(i);  // returns 18446744073216589909  (0xffffffffe29e0055)

If the code represents some type of 32-bit structure with a combination of flags and numbers, it is probably a 32-bit code based on your example.  COM errors, for example, are translated to negative 32-bit signed integers becuase the leftmost bit is always 1 for errors to indicate a failure (


Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…

734 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question