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I found a c# example that contained a for loop without any data in it but I don't understand what it means:
"for ( ; ; )"
I was always under the impression that some data needed to be included in a for loop. What does this dataless for loop achieve?
Thanks.
-Goalie35
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It's an infinite loop. Without a break or return in the loop body, this will just loop forever. Alternative ways of doing this include while (true) or while (1 == 1).
Deja View - the feeling that you've seen this post before.
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This is an infinite loop construct. Some people prefer this method for certain activities over while(true) { }. In either case these are infinite loops which can cause problems. If you don't have to use them, don't. Graceful exits to loops are always preferred.
Phil
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It's an endless loop like while (true).
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning." - Rick Cook www.troschuetz.de
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An endless loop. while ( true ) does the same thing, a little more clearly in my opinion. Come to think of it, maybe for ( ; true ; ) should be used.
--| "Every tool is a hammer." |--
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Everyone is right that previously replied except for the notion that it is not infinite.
This is infinite
for(;; );
a loop with a body may or may not be infinite depending on the existence of breaks and break conditions.
for(;; ){
...
}
Also, if you are threading a Thread Abort Exception will break any infinite loop; maybe 
The only reason I mention this is because there are important points to consider when writing or interpreting those kinds of structures.
File Not Found
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Hi,
I'm one of those programmers who use for(;;) to create what some call an
"infinite loop". I have several comments on the previous entries:
1. As a long time C programmer and having used many different compilers, I dont
write code such as if (true) ... or while(true)... simply because there are compilers
that insist on generating some silly warning ("logic expression is constant" or
something similar); I expect the same for "for(;true;)" which I never tried;
I never got warnings on for(;;) so that is the only form I use; and whoever has seen
it once, knows immediately what the intentions are.
2. I dont use a semi-colon when I want an empty code block; when I need an empty code block, I write one, that is {}.
reason: those two brackets are clearly intentional and adding/deleting one of them
would result in a compilation error, whereas a single semi-colon is easily overlooked
(so it makes it harder to read and understand the code), and adding/removing one
may yield a new source that compiles, but behaves quite differently.
3. although we all know what is meant by "infinite loop", there actually is no
such thing; everything will come to an end: either energy will run out, or
someone will stop your system, or your hardware will fail, or your software
(app or OS) will crash. Guess which one it will be ?
If you are in pursuit of an infinite loop, my first recommendation would be not
to use software in it.
for(;;) Console.WriteLine("I like C#");
Luc Pattyn
[My Articles]
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i had see the ability to do drag and drop in list view but it only for string. Can we drag and drop other than string?
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Hi all
I am having a list<objects> (business ojects) which i need to bind to a datagridview. But the problem is it displays all the properties even if it is not set.
I way to display only specific properties is to hide those columns where the value is null.
I just want to know if there is a another way to bind specific properties only and not all the properties.
Thanx
Farhan
thanx for the support
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hi
i want to call scanner program to scan an image (with code) and capture that image that scaned with scanner app,but how to do ?
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Hi,
I have created and populated a generic collection.
This is the collection.
List<List<Test>> testCurves = new List<List<test>>();
How do I loop through this collection to the lowest hierarchy please?
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foreach(List<Test> subList in testCurves)
{
foreach(Test t in subList)
{
}
}
regards
modified 12-Sep-18 21:01pm.
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Just a suggestion: foreach loops are way slower than standard for loops.
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I just tested it with a 1000*10000 nested List<List<int>> and Stopwatch-class, and this is the result:
Time for foreach-loop: 00:00:00.0980682
Time for for-loop: 00:00:00.0946116
I don't see a huge difference here.
Maybe the compiler is optimizing some things, like automatically converting it to a for-loop when it encounters a generic list.
regards
modified 12-Sep-18 21:01pm.
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foreach is easier to maintain so unless you are dealing with large collections of data I always recommend foreach over a for loop. However, for truly large data you should consider pointers.
File Not Found
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Hi all,
i am retuting an string array..but the errror is..
Cannot implicitly convert type 'string[]' to 'string'
Please help me, with a sample to return a basic array return
prashanth,
s/w Engineer,
Syfnosys.
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The error is telling you that you are trying to force a string array into a string. I assume that you are trying to return a string array, in which case the following will suffice:
public string[] GetValues()
Deja View - the feeling that you've seen this post before.
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Hi i sorry, if any big blunders
i am very new to this kind of programming plese help me
actually i have collected some values from xml file and i need to disply them
so
i wrote
public string[] GetLaserProp(string laserid, string parentnode1, string childnode1)
{
XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(@"E:\Dropdown_XML\laserProp.xml");
string[] str = new string[5];
// XmlNodeList xmlnodelst = xmldoc.GetElementsByTagName("laser");
XmlNodeList xmlnodelst = xmldoc.GetElementsByTagName(parentnode1);
//return xmlnodelst;
//foreach (XmlNode.parentnode in xmlnodelst)
foreach (XmlNode parentnode in xmlnodelst)
{
//MessageBox.Show(parentnode.Attributes.Item(0).Value);
if (parentnode.Attributes.Item(0).Value == laserid)
{
xmldoc.LoadXml(parentnode.InnerXml);
//XmlNodeList xmlchildnodelst=xmldoc.GetElementsByTagName("gauge");
XmlNodeList xmlchildnodelst = xmldoc.GetElementsByTagName(childnode1);
// cmbChildLaser.Items.Clear();
foreach (XmlNode childnode in xmlchildnodelst)
{
for (int i = 0; i < childnode.ChildNodes.Count; i++)
{
//cmbChildLaser.Items.Add(childnode.ChildNodes.Item(i).Attributes.Item(0).Value);
for (int j = 0; j < childnode.ChildNodes.Item(i).Attributes.Count; j++)
{
// MessageBox.Show(
str[j]= childnode.ChildNodes.Item(i).Attributes.Item(j).Value;
//cmbChildLaser.Items.Add(xmlnodelst1.Item(ii).ChildNodes.Item(0).InnerText);
return str;
}
}
}
}
}
//return (Student []) students.ToArray();}
return str;
prashanth,
s/w Engineer,
Syfnosys.
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Gosh! That code is very difficult to read because of all the commented out lines. This can be quite confusing.
Here is a cleaner version of the code you've supplied:
public string[] GetLaserProp(string laserid, string parentnode1, string childnode1)
{
XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(@"E:\Dropdown_XML\laserProp.xml");
string[] str = new string[5];
XmlNodeList xmlnodelst = xmldoc.GetElementsByTagName(parentnode1);
foreach (XmlNode parentnode in xmlnodelst)
{
if (parentnode.Attributes.Item(0).Value == laserid)
{
xmldoc.LoadXml(parentnode.InnerXml);
XmlNodeList xmlchildnodelst = xmldoc.GetElementsByTagName(childnode1);
foreach (XmlNode childnode in xmlchildnodelst)
{
for (int i = 0; i < childnode.ChildNodes.Count; i++)
{
for (int j = 0; j < childnode.ChildNodes.Item(i).Attributes.Count; j++)
{
str[j]= childnode.ChildNodes.Item(i).Attributes.Item(j).Value;
return str;
}
}
}
}
}
return str;
}
Which line contained the error, because I cannot see anything here that would cause the error. Perhaps, as Pete suggested, the error is in the caller.
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Colin Angus Mackay wrote: Which line contained the error, because I cannot see anything here that would cause the error.
Me neither
Colin Angus Mackay wrote: Perhaps, as Pete suggested, the error is in the caller.
agreed 
modified 12-Sep-18 21:01pm.
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You force your array to have a size of 5. What happens if you have more than 5 matches?
If you're using .NET 2, you would be better using this:
public List<string> GetLaserProp(string laserid, string parentnode1, string childnode1)
{
List<string> list = new List<string>();
XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(@"E:\Dropdown_XML\laserProp.xml");
XmlNodeList xmlnodelst = xmldoc.GetElementsByTagName(parentnode1);
foreach (XmlNode parentnode in xmlnodelst)
{
if (parentnode.Attributes.Item(0).Value == laserid)
{
xmldoc.LoadXml(parentnode.InnerXml);
XmlNodeList xmlchildnodelst = xmldoc.GetElementsByTagName(childnode1);
foreach (XmlNode childnode in xmlchildnodelst)
{
for (int i = 0; i < childnode.ChildNodes.Count; i++)
{
for (int j = 0; j < childnode.ChildNodes.Item(i).Attributes.Count; j++)
{
list.Add(childnode.ChildNodes.Item(i).Attributes.Item(j).Value);
}
}
}
}
}
return list;
}
-- modified at 10:05 Wednesday 7th March, 2007
Deja View - the feeling that you've seen this post before.
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Why not using a List<string>?
---
single minded; short sighted; long gone;
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I did, but the formatting got stripped out. (Show's I should preview my posts). I'll fix it ASAP.
Deja View - the feeling that you've seen this post before.
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Hi
I am developing a windows application in which it contains a grid. on double clicking a row on the Grid it shows all the details about that row in a new form.
If i double click the same row or other row it opens the details of respective row again in a same form.
For this i followed one logic. I take a global variable (public boolean X= false) and i am setting it true when user double clicks a row. I am resetting it in the child form. Here the value is not resetting.
What i want is Is there any mechanism or statements of code to preventing the form from openning more than one form at a time.
Please Help me.
Thanks in Advance.
Ramu Medida.
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Open the form in modal mode. Form1.ShowDialog.
This will keep it from opening another form until this one has been closed.
Make sure you call Form1.Dispose after ShowDialog because the memory is not released when using ShowDialog as with other Show methods.
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