stl container as default arguments - how?

[FBergemann]

Hi,

i wanted to merge two constructors

explicit Tokenizer (const string& token);
explicit Tokenizer (const string& token, const list<string>&
elements);

into one

explicit Tokenizer (const string& token, const list<string>&
elements = const list<string>& ());

But this doesn't compile.
What's the correct syntax?

- Thanks!

Frank

 

[Rolf Magnus]

Hi,

i wanted to merge two constructors

explicit Tokenizer (const string& token);
explicit Tokenizer (const string& token, const list<string>&
elements);

into one

explicit Tokenizer (const string& token, const list<string>&
elements = const list<string>& ());

But this doesn't compile.
What's the correct syntax?

You can't default-initialize a reference.

explicit Tokenizer (const string& token,
const list<string>& elements = list<string> ());

Note that this will create a temporary empty list whenever the default
argument is used.

 

[FBergemann]

Rolf Magnus schrieb:
[...]
thanks for the hint - but you're right:

Note that this will create a temporary empty list whenever the default
argument is used.

that's a reason to hold on two constructors for it

Regards!

Frank