QT C++ function with optional parameter for strings

Question

I'm having problem with the writing a toString function on QT C++.

For example, I have this in my header file QString toString(QString delimiter = " : "); and I get the following error

error: default argument for parameter of type 'QString' has type 'const char [3]'

The otpional parameters worked fine for other types, but it seems that the compiler interprets " : " as type char and as such gives me the following error (i thought chars use ' ', turns out i was wrong).

I googled this stuff, but couldn't find anything useless, i'm pretty there must be an easy fix to it, but I'm new to the language.

Thank you

Answer 1

The compiler error is saying that the paramater is of type QString but the default value you've given is of type const char[3] (a const character array) because it is a string literal. QString does have a constructor that takes a const char* (and remember arrays decay to pointers) so normally it would be able to perform an implicit conversion to from const char* to QString however it seems that constructor has been declared explicit and so it must be called explicitly.

Edit: It's not explicit, the header just needs to be included :)