MESSAGE
| DATE | 2011-05-24 |
| FROM | Ruben Safir
|
| SUBJECT | Re: [NYLXS - HANGOUT] [ruben@mrbrklyn.com: Re:
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From: Victor Bazarov
Newsgroups: comp.lang.c++
Subject: Re: Template argument determination
Date: Tue, 24 May 2011 11:43:26 -0400
Organization: A noiseless patient Spider
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Xref: panix comp.lang.c++:1085263
On 5/24/2011 11:04 AM, Ruben Safir wrote:
> Lets look at it this way
>
> why does this fail to compile
>
> template
> void test_me(stats::Distribution hello){
> std::cout<< "I recied an int and converted it to an object "<<
> hello<< std::endl;
> }
>
>
>
> int main ( int argc, char *argv[] ){
> int a = 7;
> test_me(a);
>
> return EXIT_SUCCESS;
> }
You ask the compiler to find what 'T' would be. During template
argument deduction the compiler does NOT use any potential promotions or
conversions. The fact that 'stats::Distribution' has a conversion
from 'int' has *no importance* to the template argument deduction
process.
>
>
> yet this does, with the promotion of the int to a distribution object
>
>
> template
> void test_me(stats::Distribution hello){
> std::cout<< "I received an int and converted it to an object "<<
> hello<< std::endl;
> }
>
>
> int main ( int argc, char *argv[] ){
> int a = 7;
> test_me(a);
Here no template argument deduction is necessary since you supplied the
argument.
>
> return EXIT_SUCCESS;
> }
V
--
I do not respond to top-posted replies, please don't ask
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