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    <p>As was noted by <a href="https://stackoverflow.com/questions/3829885/how-to-copy-a-certain-number-of-chars-from-a-file-to-a-vector-the-stl-way/3830107#3830107">Steve</a>, this would need <a href="http://www.sgi.com/tech/stl/copy_n.html" rel="nofollow noreferrer"><code>copy_n()</code></a>, which, due to an oversight, isn't in the current standard library, but will be in C++1x. You can implement one yourself easily, here's one I believe to be correct: </p> <pre><code>template&lt;class InIt, class OutIt&gt; OutIt copy_n(InIt src, OutIt dest, size_t n) { if (!n) return dest; *dest = *src; while (--n) *++dest = *++src; return ++dest; } </code></pre> <p>Note that <code>std::copy_n()</code> presumes the input iterator to be able to deliver <code>n</code> objects. When reading from a file, this could be problematic. </p> <hr> <p>Absent of <code>std::copy_n()</code>, you could use <code>std::generate_n</code>.</p> <pre><code>template&lt; typename InIt &gt; struct input_generator { typedef std::iterator_traits&lt;InIt&gt;::value_type value_type; input_generator(InIt begin, InIt end) begin_(begin), end_(end) {} value_type operator()() { assert(it_ != end); return *it_++; } Init begin_; Init end_; }; std::vector&lt;char&gt; buffer; buffer.reserve(42); std::generate_n( std::back_inserter(buffer) , 42 , input_generator(std::istream_iterator&lt;char&gt;(file)) , input_generator(std::istream_iterator&lt;char&gt;()) ); </code></pre> <hr> <p>However, I don't see this as an advantage over reading directly from the file as <a href="https://stackoverflow.com/questions/3829885/how-to-copy-a-certain-number-of-chars-from-a-file-to-a-vector-the-stl-way/3830354#3830354">avakar showed</a>. </p>
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    1. POHow to copy a certain number of chars from a file to a vector the STL-way?
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    1. COSbi's implementation was not correct for stream iterators, which read from the stream on both increment and initialization. I fixed it.
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      1. USDon Reba
    2. CO@Don: Thanks. That's the reason why even such simple algorithms should be in the std lab — it's easy to let subtle bugs slip even into the most simple ones.
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