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c++ Programming Glossary: timeWhy is processing a sorted array faster than an unsorted array? http://stackoverflow.com/questions/11227809/why-is-processing-a-sorted-array-faster-than-an-unsorted-array up the code by almost 6x #include algorithm #include ctime #include iostream int main Generate data const unsigned arraySize.. can restart down the other path. If you guess right every time the train will never have to stop. If you guess wrong too often.. If you guess wrong too often the train will spend a lot of time stopping backing up and restarting. Consider an if statement..
What is the copy-and-swap idiom? http://stackoverflow.com/questions/3279543/what-is-the-copy-and-swap-idiom in the code self assignment rarely occurs so most of the time this check is a waste. It would be better if the operator could.. it should really be called The Big Three and A Half any time your class manages a resource it also makes sense to provide..
What can I use to profile C++ code in Linux? http://stackoverflow.com/questions/375913/what-can-i-use-to-profile-c-code-in-linux way to find performance problems. Just halt it several times and each time look at the call stack. If there is some code.. performance problems. Just halt it several times and each time look at the call stack. If there is some code that is wasting.. there is some code that is wasting some percentage of the time 20 or 50 or whatever that is the probability that you will catch..
http://stackoverflow.com/questions/4172722/what-is-the-rule-of-three and released in the destructor. Let us go back in time to pre standard C . There was no such thing as std string and.. operator const person that delete The rule of three Sometimes you need to implement a class that manages a resource. Never.. standard or any compiler I am aware of. Advice Most of the time you do not need to manage a resource yourself because an existing..
Undefined Behavior and Sequence Points http://stackoverflow.com/questions/4176328/undefined-behavior-and-sequence-points author Steve Summit Sequence point is a point in time at which the dust has settled and all side effects which have..
http://stackoverflow.com/questions/4421706/operator-overloading many users sort answers according to votes rather than the time they were given here's an index of the answers in the order.. use case for these 2 . 1 As with all rules of thumb sometimes there might be reasons to break this one too. If so do not.. type otherwise their implementation results in a compile time error. The unary address of operator should never be overloaded...
Where and why do I have to put the “template” and “typename” keywords? http://stackoverflow.com/questions/610245/where-and-why-do-i-have-to-put-the-template-and-typename-keywords to cast a Union bool float to std string is a compile time error. The simple solution was to add a template typename U.. you will often get parser errors already at definition time t x is taken as non type but as an expression the following..
Can a local variable's memory be accessed outside its scope? http://stackoverflow.com/questions/6441218/can-a-local-variables-memory-be-accessed-outside-its-scope cout p p 8 cout p And the code is just running with no runtime exceptions The output was 5 8 How can it be Isn't the memory.. ways of generating code to manage memory but over time two basic techniques have become entrenched. The first is to.. to have some sort of long lived storage area where the lifetime of each byte in the storage that is the period of time when..
mixing cout and printf for faster output http://stackoverflow.com/questions/1924530/mixing-cout-and-printf-for-faster-output std cout n count string int main show_time use_printf Time using printf show_time use_puts Time using puts show_time use_cout.. show_time use_printf Time using printf show_time use_puts Time using puts show_time use_cout Time using cout synced show_time.. show_time use_puts Time using puts show_time use_cout Time using cout synced show_time use_cout_unsync Time using cout..
http://stackoverflow.com/questions/4707012/c-memcpy-vs-stdcopy to the performance of my algorithm. These are my results Time in seconds to complete run of SHA 2 tests std copy memcpy increase.. set of 5 test strings. These are my final 10 results Time in seconds to complete run of MD5 tests std copy memcpy difference.. These are my results with LTO turned on option flto in gcc Time in seconds to complete run of MD5 tests with flto std copy memcpy..
How to determine CPU and memory consumption from inside a process? http://stackoverflow.com/questions/63166/how-to-determine-cpu-and-memory-consumption-from-inside-a-process PdhAddCounter cpuQuery L Processor _Total Processor Time NULL &cpuTotal PdhCollectQueryData cpuQuery double getCurrentValue.. numProcessors sysInfo.dwNumberOfProcessors GetSystemTimeAsFileTime &ftime memcpy &lastCPU &ftime sizeof FILETIME self.. sysInfo.dwNumberOfProcessors GetSystemTimeAsFileTime &ftime memcpy &lastCPU &ftime sizeof FILETIME self GetCurrentProcess..
Windows 7 timing functions - How to use GetSystemTimeAdjustment correctly? http://stackoverflow.com/questions/7685762/windows-7-timing-functions-how-to-use-getsystemtimeadjustment-correctly 7 timing functions How to use GetSystemTimeAdjustment correctly I ran some tests using the GetSystemTimeAdjustment.. correctly I ran some tests using the GetSystemTimeAdjustment function on Windows 7 and got some interesting results.. and with which increment it is updated see GetSystemTimeAdjustment function on MSDN . From this I follow that if I query..
Copy a file in an sane, safe and efficient way http://stackoverflow.com/questions/10195343/copy-a-file-in-an-sane-safe-and-efficient-way end clock cout CLOCKS_PER_SEC CLOCKS_PER_SEC n cout CPU TIME START start n cout CPU TIME END end n cout CPU TIME END START.. CLOCKS_PER_SEC n cout CPU TIME START start n cout CPU TIME END end n cout CPU TIME END START end start n cout TIME SEC.. CPU TIME START start n cout CPU TIME END end n cout CPU TIME END START end start n cout TIME SEC static_cast double end start..
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