Re: [Boost-users] Problems using for_each

Subject: Re: [Boost-users] Problems using for_each
From: Will Mason (willchido_at_[hidden])
Date: 2013-03-31 13:08:15

Hello,

On Sun, Mar 31, 2013 at 10:56 AM, Michael Powell <mwpowellhtx_at_[hidden]>wrote:

> Hello,
>
> I am struggling making for_each work right. I am using Sourcery
> targeting ARM. AFAIK, GCC is actually 4.7.2, and I am flagging
> -std=c++11.
>
> I'm not really picky how we get for_each done (or constructs like it).
> I'd like to avoid "macro-expansion" for obvious reasons (i.e. debug),
> and the always-infamous verbosity of a for loop, if possible.
>
> I've got the following:
>
> vector<rgb_type*> all;
> rgb_type rgb;
> rgb_type rgb2 = rgb.clone();
>
> for_each(all.begin(), all.end(), cout << _1->r() << endl);
>

Since you are using gcc 4.7.2 with -std=c++11, you can just use a std
lambda here:

std::for_each(all.begin(), all.end(), [] (rgb_type* val) { std::cout <<
val->r() << std::endl; });

Cheers,
Will

>
> With errors:
>
> _1 was not declared in this scope. (C++ Problem)
>
> That or,
>
> void rgb_printer_func(rgb_type* prgb) {
>   cout << prgb->r() << endl;
> }
>
> for_each(all.begin(), all.end(), rgb_printer_func);
>
> With errors:
>
> Invalid arguments Candidates are: #1 for_each(#0, #0, #1) (Semantic Error)
>
> Thank you.
>
> Regards,
>
> Michael Powell
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