I seem to keep running into little tidbits that help drastically in different areas of different languages.
For instance, a few days ago I learned about EXPLAIN SELECT... for any MySQL query that seems to be going slow. It took my 196 second query to 0.0084 seconds.
I'm a young programmer, so all my working life I've been told GOTO is evil, don't use it, if you do, your first born son will die.
Recently, I've realized that GOTO actually still exists in .NET and I was wondering, is GOTO really as bad as they say, or is it just because everyone says you shouldn't use it, so that's why you don't.
I know GOTO can be used badly, but are there any legit situations where you may possibly use it.
The only thing I can think of is maybe to use GOTO to break out of a bunch of nested loops. I reckon that might be better then having to "break" out of each of them but because GOTO is supposedly always bad, I would never use it and it would probably never pass a peer review.
What are your views? Is GOTO always bad? Can it sometimes be good? Has anyone here actually been gutsy enough to use GOTO for a real life system?
I've seen lots of codes have declaration like Class clazz , where does this originate from ? Is this some kind of convention ? I think 'clazz' is not even a English word , has no meaning at all .
I have IP cam that supports RTSP streaming. It's connected to router with 2 network cards with IP1 and IP2 addresses. I make 2 connections to IP cam by IP1 and IP2 addresses from the same IP and I need to receive corresponding streams thru correct network card, but both streams (RTP over UDP) go thru IP1. How this can be resolved?
I don't know if RTSP server binds UDP sockets to corresponding IP and I don't know what IP stack is in IP cam (weak end system or strong end system). I haven't found anything interesting in router configuration. As I understand, routing table cannot help me cos I'm connected from the same IP, is it right? Also
Sorry for incomplete info but it's all I have at the moment. Thanks for your time.
Hi,
Is there a wiki or book, which explains what happens when user enters a link in the browser, and how the dns is resolved, how the router finds the route to the host etc.. I am mainly interested in routing the packets.
Thank you
Hi,
I am looking for a C++ library for image processing. I need the library to threshold a PPM photo (color photo). Should I write my own code? what do you guys think? Thanks in advance.
I know this thing works:
void myDisplay()
{
...
}
int main()
{
...
glutDisplayFunc(myDisplay)
...
}
so I tried to include myDisplay() function to a class that I made. Because I want to overload it in the future with a different class. However, the compiler complains that
argument of type 'void (ClassBlah::)()' does not match 'void(*)()' .
Here is the what I try to make:
class ClassBlah
{
....
void myDisplay()
....
}
......
int main()
{
...
ClassBlah blah
glutDisplayFunc(blah.myDisplay)
...
}
Does anybody knows how to fix this problem? Many thanks.
How to write a kernel module that creates a directory in /proc named mymod and a file in it name is mymodfile. This file should accept a number ranged from 1 to 3 when written into it and return the following messages when read based on the number already written into it:
• 1: Current system time (in microseconds precision)
• 2: System uptime
• 3: Number of processes currently in the system
“The Output”
root@Paradise# echo 1 > /proc/mymod/mymodfile
root@Paradise# cat /proc/mymod/mymodfile
08:30:24 342us
root@Paradise# echo 2 > /proc/mymod/mymodfile
root@Paradise# cat /proc/mymod/mymodfile
up 1 day, 8 min
root@Paradise# echo 3 > /proc/mymod/mymodfile
root@Paradise# cat /proc/mymod/mymodfile
process count: 48
please give me some hint how to write a kernel modules and how to compile and install it .
I am calling another shell script testarg.sh within my main script.
the logfiles of testarg.sh are stored in $CUSTLOGS in the below format
testarg.DDMONYY.PID.log
example: testarg.09Jun10.21165.log
In the main script after the testarg process gets completed i need to grep the log file for the text "ERROR" and "COMPLETED SUCCESSFULLY".
How do i get the PID of the process and combine with DDMONYY for grepping. Also i need to check whether file
exists before grepping
$CUSTBIN/testarg.sh
$CUSTBIN/testarg.sh
rc=$?
if [ $rc -ne 0 ]; then
return $CODE_WARN
fi
How to get the UTC time in milliseconds under windows platform. I am using Standard library which give me UTC time in seconds, I want to get time in miliseconds, kindly give me the reference of any other library which give me the accurate UTC time in miliseconds.
I have the following code:
$sql = "SELECT name, address, city FROM tableA, tableB WHERE tableA.id = tableB.id";
if (isset($price) ) {
$sql = $sql . ' AND price = :price ';
}
if (isset($sqft) ) {
$sql = $sql . ' AND sqft >= :sqft ';
}
if (isset($bedrooms) ) {
$sql = $sql . ' AND bedrooms >= :bedrooms ';
}
$stmt = $dbh->prepare($sql);
if (isset($price) ) {
$stmt->bindParam(':price', $price);
}
if (isset($sqft) ) {
$stmt->bindParam(':price', $price);
}
if (isset($bedrooms) ) {
$stmt->bindParam(':bedrooms', $bedrooms);
}
$stmt->execute();
$result_set = $stmt->fetchAll(PDO::FETCH_ASSOC);
What I notice is the redundant multiple IF statements I have.
Question: is there any way to clean up my code so that I don't have these multiple IF statements for prepared statements?
Uninstalled VS2010 Beta 2.
Uninstalled .NET Framework 4 Extended Beta 2.
On attempting to uninstall .NET Framework 4 Client Profile Beta 2. I get
Blocking Issues:
You must uninstall the .NET Framework 4 Extended Beta 2 before you uninstall the .NET Framework 4 Client Profile Beta 2.
On attempting to reinstall Framework 4 Beta 2 I get:
Details:
Same or higher version of .NET Framework 4 Beta 2 has already been installed on this computer.
Please help!
Can I simply remove registry entries and the C:\WINDOWS\Microsoft.NET\Framework\v4.0.21006 directory?
As a result of a conversation with a colleague today, I've been searching (unsuccessfully) for a large'ish list of what technology stacks are being used popular websites and standalone applications today. We're aware of the big ones like Facebook (php/ ), Twitter (scala/cassandra), Youtube (python/?), Digg (php/cassandra), stackoverflow (.net mvc/sqlserver), but we're looking for a more complete list. It would also be interesting to hear about any stats for desktop apps also?
Can anyone help?
Well i got this job offer and they expect alot i say. i know most of this but, i would like to know what type of pay i should expect. I dont well to sell short you know.
with Web Designer: Dreamweaver, HTML, JavaScript, Graphic Design/Manipulation, Templates, Layouts, Navigation, Flash/Multimedia Objects. Programmer: PHP, Web Application Development, MVC, Joomla, AJAX, JQuery, My SQL (SQL, Database).
Following features to remove from c++ and desired features for c++ I thought why not complete the trio... what features are you happy about in C++ and don't want to change at all? What features are elegantly and brilliantly implemented and still look better than other more modern languages
I am validating input on a form and attempting to prompt the user of improper input(s) based on the combination of controls used.
For example, I have 2 combo boxes and 3 text boxes. The 2 combo boxes must always have a value other than the first (default) value, but one of three, or two of three, or all text boxes can be filled to make the form valid.
In one such scenario I have a 6 line if statement to try to make the test easily readable:
if ((!String.Equals(ComboBoxA.SelectedValue.ToString(), DEFAULT_COMBO_A_CHOICE.ToString())
&& !String.IsNullOrEmpty(TextBoxA.Text)
&& !String.Equals(ComboBoxB.SelectedValue.ToString(), DEFAULT_COMBO_B_CHOICE.ToString()))
||
(!String.IsNullOrEmpty(TextBoxB.Text)
|| !String.IsNullOrEmpty(TextBoxC.Text)))
{
//Do Some Validation
}
I have 2 questions:
Should this type of if statement be avoided at all cost?
Would it be better to enclose this test in another method? (This would be a good choice as this validation will happen in more than one scenario)
Thanks for your input(s)!
I am writing a server application that will provide a service on an ephemeral port that I only want accessible on the loopback interface. In order to do this, I am writing code like the following:
struct sockaddr_in bind_addr;
memset(&bind_addr,0,sizeof(bind_addr));
bind_addr.sin_family = AF_INET;
bind_addr.sin_port = 0;
bind_addr.sin_addr.s_addr = htonl(inet_addr("127.0.0.1"));
rcd = ::bind(
socket_handle,
reinterpret_cast<struct sockaddr *>(&bind_addr),
sizeof(bind_addr));
The return value for this call to bind() is -1 and the value of errno is 99 (Cannot assign requested address). Is this failing because inet_addr() already returns its result in network order or is there some other reason?
When coding, I often come across the following pattern:
-A method calls another method (Fine), but the method being called/callee takes parameters, so in the wrapping method, I pass in parameters. Problem is, this dependency carrying can go on and on. How could I avoid this (any sample code appreciated)?
Thanks
I know that the additional consideratiosn when compiling for x64 is that some data types, like ints, can hold larger values. Are there any concerns?
VS2010, released a few days ago, can support compiling for x64 and x32, just like VS2008. The app is x32/86 only. I keep thinking that the app needs to be 64 bit however. What am I missing? Obviously this is not the case.
Thanks
I'm trying to write a rogue-like game for my blackberry and hopefully
any other phone that supports some sort of JVM.
Because I use Java in my job I'm looking to write the game in another language but I cannot find a language that will work on multiple phones.
Am I stuck with Java?