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How to round a number to n decimal places in Java
... this IS WAY faster than using DecimalFormat. I looped using DecimalFormat 200 times, and this method. DecimalFormat took 14ms to complete the 200 loops, this method took less than 1ms. As I suspected, this is faster. If you get paid by the clock cycle, this is what you should be doing. I'm surprise...
Why do we use volatile keyword? [duplicate]
... code. Now search the web to see some sample examples.
Quoting from the C++ Standard ($7.1.5.1/8)
[..] volatile is a hint to the
implementation to avoid aggressive
optimization involving the object
because the value of the object might
be changed by means undetectable by an
implemen...
upstream sent too big header while reading response header from upstream
...2s harder to hit but not impossible, e.g native:
bash-4.1# for it in {30..200..3}; do for size in {100..250..3}; do echo "size=$size iterations=$it $(curl -sv "http://localhost/debug.php?size=$size&iterations=$it" 2>&1 | egrep '^< HTTP')"; done; done | grep 502 | head
size=121 iterati...
Which is the best Linux C/C++ debugger (or front-end to gdb) to help teaching programming? [closed]
I teach a sort of "lite" C++ programming course to novices ("lite" meaning no pointers, no classes, just plain old C, plus references and STL string and vectors). Students have no previous experience in programming, so I believe that using an interactive debugger would help them understand program f...
How do I list the symbols in a .so file
... it simply like this:
nm -gD yourLib.so
If you want to see symbols of a C++ library, add the "-C" option which demangle the symbols (it's far more readable demangled).
nm -gDC yourLib.so
If your .so file is in elf format, you have two options:
Either objdump (-C is also useful for demangling ...
Error: free(): invalid next size (fast):
What is this strange error I'm getting? I'm compiling C++ using g++ on Ubuntu 10.10. It pops up randomly when I run the executable (maybe 2 times in 8 hours, with 10 compiles an hour). However, if I make clean and recompile it goes away most of the time.
...
In CMake, how can I test if the compiler is Clang?
... cross-platform CMake build scripts , and we support building with Visual C++ and GCC .
5 Answers
...
std::string to float or double
... "0.6";
double temp = ::atof(num.c_str());
Does it for me, it is a valid C++ syntax to convert a string to a double.
You can do it with the stringstream or boost::lexical_cast but those come with a performance penalty.
Ahaha you have a Qt project ...
QString winOpacity("0.6");
double temp = w...
What is the difference between linear regression and logistic regression?
...anted to predict, based on size, whether a house would sell for more than $200K, you would use logistic regression. The possible outputs are either Yes, the house will sell for more than $200K, or No, the house will not.
sha...
How to detect a Christmas Tree? [closed]
...ng");
// 1. Threshold
threshold.setAttribute("threshold", 200);
threshold.process(tree.clone(), tree);
}
}
public static void main(String[] args) {
new ChristmasTree();
}
}
In the second step, the brightest points in the image are dilated in order to form shapes. T...