On Oct 12, 3:22 pm, Adam Nielsen <adam.niel...@remove.this.uq.edu.au>
wrote:
> I'm trying to work out how to construct a temporary object in a class'
> initialisation list and then call a function on it, in order to pass the
> result to a base class' constructor.
> struct PrintNumber: public PrintString
> {
> PrintNumber(int iNumber)
> : PrintString(
> // How should this be done?
> (std:stringstream() << "The number is " << iNumber).str()
> )
> {
> }
> };

I would write:

struct PrintNumber: public PrintString
{
PrintNumber(int iNumber) : PrintString( convert_number(iNumber) ) {}

private:
std::string convert_number(int n)
{
std:stringstream oss;
oss << "The number is " << n;
return oss.str();
}
};

On Oct 17, 1:03 am, Old Wolf <oldw...@inspire.net.nz> wrote:
> On Oct 12, 3:22 pm, Adam Nielsen <adam.niel...@remove.this.uq.edu.au>
> wrote:

> > I'm trying to work out how to construct a temporary object in a class'
> > initialisation list and then call a function on it, in order to pass the
> > result to a base class' constructor.
> > struct PrintNumber: public PrintString
> > {
> > PrintNumber(int iNumber)
> > : PrintString(
> > // How should this be done?
> > (std:stringstream() << "The number is " << iNumber).str()
> > )
> > {
> > }
> > };

> I would write:

> struct PrintNumber: public PrintString
> {
> PrintNumber(int iNumber) : PrintString( convert_number(iNumber) ) {}

> private:
> std::string convert_number(int n)

I'm not sure that it's absolutely necessary, but I'd make this
function static. If the constructors that use it are all in a
single file, I'd put it in an anonymous namespace in the file,
rather than making it a member. And in the very particular case
here, there is some argument for making it a static protected
template member of the base class (but that's not usually
applicable).

--
James Kanze (GABI Software) email:james.kanze@gmail.com
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