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Hey thanks Pete for the idea but if you have the time could you tell me where is the setting to accomplish this.... thank you in advance
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Hey All,
A very happy new year to you all. I am working on GoF design patterns. I want to know if it is feasible or possible to make a library like STL for design patterns using .net Generics? If there are some existing projects like this can someone please send me links to it?
thanks
RB
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I doubt that this is possible. I do not design my algorithms just for their own sake, but rather dependent on the infrastructure and related classes of the project where I need the classes in.
But on the other hand, maybe you come up with a great solution. I would be the first to use it  !
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I am not making classes just for the sake of it. What i have in mind is that like in STL to have a list of student what we can do is List<cstudent> s_list similarly i was looking to do something like if we need a single student object in our object..we do not need to make the student class singleton but only keep the object singleton like Singleton<student> ss = new Singleton<student>();
Do you still think its impossible?
thanks
RB
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hi
i have a string and i want to search a string and navigate into this string,but how to do ?
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See IndexOf() and IndexOfAny().
/ravi
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Look at the Substring method on the String class.
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I am looking at converting some C++ code to C# and i have a few questions. My experience with C++ is severely limited, mostly to some recoding of Quake 3 and Half-life 2 source code, just fooling around with modding.
i am not 100% clear on the function of header files, and would like to know if there is a need to, and easy(ish) way to emulate the behavior of header files in C#.
if they simply contain large groups of static variables? should it then be a simple task of taking the contents of a header file and rewrite it as a bunch of static variables in the program.cs file (or wherever they may be used)?
______________________
Mr Griffin, eleventy billion is not a number...
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Vodstok wrote: if there is a need to, and easy(ish) way to emulate the behavior of header files in C#.
There is no need. Header files in C++ are a way to tell the compiler and other class files which functions are in a class.
C# has no such restriction, just declare all variables, methods, symbols, etc. right inside the class file, no header required.
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That makes me very happy Thank you.
______________________
Mr Griffin, eleventy billion is not a number...
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I posted my experiences when porting an application here [^].
Maybe it is of some value to you .
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Every little bit helps
______________________
Mr Griffin, eleventy billion is not a number...
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how can I make activex (.ocx) file
in c#?
I have a software that can get .ocx files
and not .dll files
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You can't. C#, VB.NET and the other managed-code languages can't target building an old .OCX file. It can still be done using C++ though. The managed languages can "emulate" a COM component by COM-interop, but they cannot build an exact binary replacement for them.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Hi gurus!
I’m creating a large array that holds the distances from all points in a location file (x and y coordinates) to all other points. I have no control over how many locations the user will input (thousands most likely) so with the number of distances to record at (n(n-1)/2), I’m going to be storing a helluva lot of values. As I want to use these in a Monte Carlo simulation and access each value up to 999 times, I would prefer to calculate the distance matrix only once and not have to recalculate each distance every iteration of the MC simulation.
I would appreciate advice on the most efficient way to store and quickly access these values: ArrayList, Hashtable, Queue or something else?
 A secondary question. Is what I am trying to achieve just unmanageable? For example, with the user including 10,000 locations, that creates 49 million distance calculations. How will this affect access time to reading the values again and again…?
TIA
Jerry
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Hi,
if your distances are theoretical, why not just store city coordinates, and calculate
the distance every time you need it?
If it is actual distances, you will need to store of course; maybe a random-access
file on disk is appropriate.
In any case, I would be worried more about elpased time for your program,
when it will deal with 10000 cities visited 999 times...
I hope it is not a brute force attempt to the travelling salesman problem !
Luc Pattyn
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I'm afraid I'm not familiar with the travelling salesman problem, so it isn't that!
The Monte Carlo simulation is one that keeps the spatial locations constant, but randomises a third variable (the first two being x and y location), and yes, these are real locations. My concern with recalculating the distances every time is that with 10,000 locations, that creates 49 million distance calculations. With 999 iterations of the Monte Carlo simulation (1000 with the observed outcome), that means that to complete the program requires 1,000 x 49 million distance calculations  . Hence my desire to only do the 49 million calculations once and then store the results in an array that I access the remaining 999 times.
Do you (or anyone else out there) think that recalculating the distances every iteration for 999 times will be quicker than storing the distance results in an array or a file and accessing them repeatedly?
Jerry
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I still dont know what you want to do in each run, e.g. I am not sure you need
all the distances everytime.
If each run only needs "a few", do lazy calculation (i.e. only what is needed),
if you need all of them every time, I would go for the (large) file on disk,
which will automatically get cached when your code reads the relevant entries.
Also, how complex is one iteration ? is it much larger than calculating the
distances it needs, or not ?
Can you be more specific ?
Luc Pattyn
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I need every distance, every time. The program is designed to conduct a new statistical process on locations that have a date attached. Think something like bird spotting. I have, say 10,000 records with an x and y coordinate and the date of observation. The program measures the distance between each point to every other point, and also measures the number of days between each observation. It then randomizes the day, and repeats the process 999 times, randomizing the days each time. The distance between points therefore remains constant and does not need to be recalculated, but it does need to be remembered every one of the 999 iterations, becuase it categorizes the results by distance. And there will be 49 million distances to remember.
The question therefore remains, for speed do I recalculate the distance every time on the fly, or save in a file, or save in an arrayList, Hashtable or Queue...?
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OK, I start to get the picture.
Your basic information consists of some 10000 points (that could be 80KB of data).
So it seems very wasteful to expand that to a full distance matrix (some 50MB).
Let us assume that distance simply equals SQRT(dx*dx+dy*dy).
I did a simple experiment: the following code
double z=0.0;
for (int dx=0; dx<10000; dx++) {
for (int dy=0; dy<10000; dy++) {
z+=Math.Sqrt(dx*dx+dy*dy);
}
}
Console.WriteLine(z);
took less than 4 seconds on a 1.7GHz Pentium M.
Using a file on disk would certainly be faster (A large part of your file would
typically be in the file cache in memory, which gets refilled at the disk's
transfer rate, typically 100 MB/sec or more). So I expect consuming 50MB would take
under 1 second (you could try that with another 50 lines of code...)
On the other hand, the (lack of) speed of the above code is mainly due to the
Math.Sqrt() method; if we replace that line by z+=dx*dx+dy*dy; it runs in less
than 0.7 seconds.
Preliminary conclusions:
- if you are lucky and only need the square of the distances, go for direct calculation;
- if you are unfortunate and need a more complex calculation for distances (the earth
being round, remember), go for the file on disk.
- it may be worthwhile to investigate faster SQRT methods (maybe int based, maybe
slightly less accurate, whatever).
My suggestion:
I would certainly start of with direct calculation and see how it is behaving
before introducing a file-based optimization (the rule is: think first, then code
and get it working without unnecessary complications, then observe and
only then make changes, and introduce complexity, to improve).
Luc Pattyn
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This helps a lot, thanks! 
I hadn't considered that the SQRT function was so time consuming, but given the iterations that I have, that is a big factor. I'll try what you suggest.
Cheers.
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Hi,
I'd like to write a basic parser in XML to write the values of various fields across several forms to a text file. The idea is that custom settings of all these fields can be stored as a "user config" that can be recalled.
Could you help point me towards information online that will help me get started? I would like to start with a test app that writes several values to a text file and then reads then back into the form.
Thanks!
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See this[^] set of tutorials.
/ravi
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Thank you! Do you know of a similar set of tutorials for C#?
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The tutorial supports both VB and C#.
/ravi
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