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I would like to know what is the most efficient and practical way of sending a Qstring as a parameter to a function, in QT more specifically. I want to use a reference. The problem is I also want to instantiate that string in the function itself like so for example:
this is the function prototype:
void myFunction(QString & theMsg); this is the function call:
myFunction(tr("Hello StringWorld")); now the function tr() returns a QString but it doesn't work with a reference(I can see why).
I have to do this:
QString theQstr("Hello StringWorld"); myFunction(theQstr); Is there a simpler way to do this while still using references or could I just change the function parameter to use a QString and it would still be efficient?
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One way to initialize a QString is simply to pass a const char * to its constructor. For example, the following code creates a QString of size 5 containing the data "Hello": QString str = "Hello"; QString converts the const char * data into Unicode using the fromAscii() function.
To break up a string into a string list, we used the QString::split() function. The argument to split can be a single character, a string, or a QRegExp. To concatenate all the strings in a string list into a single string (with an optional separator), we used the join() function.
You can use: QString qs; // do things std::cout << qs. toStdString() << std::endl; It internally uses QString::toUtf8() function to create std::string, so it's Unicode safe as well.
QString uses COW (Copy On Write) behind the scenes, so the actual string isn't copied even if you use a signature like this:
void myFunction(QString theMsg)
(until you modify it that is).
If you absolutely want a reference I would use a const& unless you plan to modify the input argument.
void myFunction(QString const& theMsg)
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