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Is it better in C++ to pass by value or pass by constant reference?

...d be able to figure out when passing by value is expensive, and implicitly convert the call to use a const ref if possible. In theory. In practice, compilers can’t always change this without breaking the function’s binary interface. In some special cases (when the function is inlined) the copy ...
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How to get a list of user accounts using the command line in MySQL?

...| root | demohost | | root | 127.0.0.1 | | debian-sys-maint | localhost | | | % | +------------------+-----------+ share | improve this answer ...
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Making the iPhone vibrate

...rror for trying to cast from Int to UInt32, but the error reads as "Cannot convert to SystemSoundID", which is confusing. Why didn't apple just make it a Swift enum is beyond me. @aponomarenko's goes into the details, my answer is just for the Swifters out there. ...
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Writing to an Excel spreadsheet

...ures and will let you read in excel files as well. You will first have to convert your data into a DataFrame and then save it into an excel file like so: In [1]: from pandas import DataFrame In [2]: l1 = [1,2,3,4] In [3]: l2 = [1,2,3,4] In [3]: df = DataFrame({'Stimulus Time': l1, 'Reaction Time':...
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Group by with multiple columns using lambda

... Balance = g.Sum(x => Math.Round(Convert.ToDecimal(x.Worth), 2)), } ); foreach (var item in CompanyDetails) { Console.WriteLine(item.Typ...
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Why is address zero used for the null pointer?

... differently at runtime. The C++ standard has a note that makes clear that converting "an integral constant expression with value zero always yields a null pointer, but converting other expressions that happen to have value zero need not yield a null pointer". a negative value might be just as usabl...
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“rm -rf” equivalent for Windows?

...lder /c /G "ADMINNAME":F /T rmdir /s folder Works for anything including sys files EDIT: I actually found the best way which also solves file path too long problem as well: mkdir \empty robocopy /mir \empty folder share...
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How do I format a number in Java?

... When you want to convert the rounded value as string, this is one of the way. Other is using DecimalFormat. And DecimalFormat is slightly faster than String.format. Simple System.currentTimeMillis diff reveals that. – ma...
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Can you get the column names from a SqlDataReader?

...numerable<dynamic>> and .Cast<dynamic>, but it says, Cannot convert method group 'Cast' to non-delegate type 'dynamic'. Did you intend to invoke the method? what did I do wrong there? (I looked at your sources, but they required you to know the column name, which I don't) ...
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Detecting WPF Validation Errors

...ding Path=(validationScope:Scope.HasErrors), Converter={local:BoolToBrushConverter}, ElementName=Form}" BorderThickness="1"> <StackPanel x:Name="Form" validationScope:Scope.ForInputTypes="{x:Static validationScope:InputTyp...