Solved Constructor of a derived class
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Dear all,
I've defined a class Unh derived from Segment. The base class has a constructor Segment(QString str), and the derived class has a constructor Unh(QString str):
In the header file:
public:
Unh(QString str);
In the source file:
Unh::Unh(QString str):Segment(QString str) { ... }
I get the following error for the line in the source file while compiling:
expected primary-expression before 'str'
How can this error be got rid of? What is primary-expression anyway? Thanks for any hint!
Weichao -
Hi,
It's
: Segment(str)
. That's a call to the base class constructor, so you should pass it the variables it needs.On a side note, you should rather use const references when passing QString around like that, this will minimise the number of copies.
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@SGaist
Thank you! This is the reason. I've ignored it.
Where should I insert const to do that as you suggested? Thanks! -
Unh(constr QString& str)
By the way, you should make that constructor explicit, otherwise you might encounter funky stuff due to implicit conversion.
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@SGaist
Many thanks!