|  | adapter function for for_each | | |
| | | dominolog |  |
|  Posted: Wed Aug 20, 2008 10:28 pm Post subject: adapter function for for_each |  |
Hello
I've got following container:
std::vector<boost::shared_ptr<std::string> > strings;
strings.push_back( boost::shared_ptr<std::string> ( new
std::string("AAA") ) );
strings.push_back( boost::shared_ptr<std::string> ( new
std::string("BBB") ) );
strings.push_back( boost::shared_ptr<std::string> ( new
std::string("BBB") ) );
std::for_each( strings.begin(), strings.end(),
std::mem_fun( &std::length ) );
Now I want a 0-parameter method from std::string to be called on every
element from the sequence. I tried to use std::mem_fun (as above), but
it claims as follows:
| Quote: | cannot convert parameter 1 from 'boost::shared_ptr<T>' to 'const std::basic_string<_Elem,_Traits,_Ax> *'
|
The question is - how to construct a correct adapter for it, not using
a custom operand class. I want to use only stl stuff.
Thanks
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| |
| | | Greg Herlihy | |
| | Posted: Thu Aug 21, 2008 1:28 pm Post subject: Re: adapter function for for_each | |
| |  | |
On Aug 20, 3:28 pm, dominolog <dominiktomc...@gmail.com> wrote:
| Quote: | I've got following container:
std::vector<boost::shared_ptr<std::string> > strings;
strings.push_back( boost::shared_ptr<std::string> ( new
std::string("AAA") ) );
....
std::for_each( strings.begin(), strings.end(),
std::mem_fun( &std::length ) );
Now I want a 0-parameter method from std::string to be called on every
element from the sequence. '
The question is - how to construct a correct adapter for it, not using
a custom operand class. I want to use only stl stuff.
|
Use std::tr1::mem_fn(). For example:
#include <tr1/memory>
#include <tr1/functional>
#include <string>
#include <vector>
#include <algorithm>
using std::string;
using std::tr1::shared_ptr;
using std::tr1::mem_fn;
int main()
{
std::vector< shared_ptr<string> > v;
std::for_each(v.begin(), v.end(), mem_fn(&string::length));
}
Greg
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