using STL to find all elements in a vector

I have a collection of elements that I need to operate over, calling member functions on the collection:

std::vector<MyType> v;
... // vector is populated

For calling functions with no arguments it's pretty straight-forward:

std::for_each(v.begin(), v.end(), std::mem_fun(&MyType::myfunc));

A similar thing can be done if there's one argument to the function I wish to call.

My problem is that I want to call a function on elements in the vector if it meets some condition. std::find_if returns an iterator to the first element meeting the conditions of the predicate.

std::vector<MyType>::iterator it  = 
      std::find_if(v.begin(), v.end(), MyPred());

I wish to find all elements meeting the predicate and operate over them.

I've been looking at the STL algorithms for a "find_all" or "do_if" equivalent, or a way I can do this with the existing STL (such that I only need to iterate once), rather than rolling my own or simply do a standard iteration using a for loop and comparisons.

c++ stl

Edit Report

I wrote a for_each_if() and a for_each_equal() which do what I think you're looking for.

for_each_if() takes a predicate functor to evaluate equality, and for_each_equal() takes a value of any type and does a direct comparison using operator ==. In both cases, the function you pass in is called on each element that passes the equality test.

/* ---

    For each
    25.1.1

        template< class InputIterator, class Function, class T>
            Function for_each_equal(InputIterator first, InputIterator last, const T& value, Function f)

        template< class InputIterator, class Function, class Predicate >
            Function for_each_if(InputIterator first, InputIterator last, Predicate pred, Function f)

    Requires:   

        T is of type EqualityComparable (20.1.1) 

    Effects:    

         Applies f to each dereferenced iterator i in the range [first, last) where one of the following conditions hold:

            1:  *i == value
            2:  pred(*i) != false

    Returns:    

        f

    Complexity: 

        At most last - first applications of f

    --- */

    template< class InputIterator, class Function, class Predicate >
    Function for_each_if(InputIterator first, 
                         InputIterator last, 
                         Predicate pred, 
                         Function f)
    {
        for( ; first != last; ++first)
        {
            if( pred(*first) )
                f(*first);
        }
        return f;
    };

    template< class InputIterator, class Function, class T>
    Function for_each_equal(InputIterator first, 
                            InputIterator last, 
                            const T& value, 
                            Function f)
    {
        for( ; first != last; ++first)
        {
            if( *first == value )
                f(*first);
        }
        retur


                        
                        
                            answered 2008-10-24T17:40:39.197

using STL to find all elements in a vector

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