Re: cout << vector<string>

From:
"rio" <a@b.c>
Newsgroups:
comp.lang.c++
Date:
Sun, 9 Nov 2008 10:24:42 +0100
Message-ID:
<4916aba2$0$40315$4fafbaef@reader5.news.tin.it>
"Kai-Uwe Bux" <jkherciueh@gmx.net> ha scritto nel messaggio
news:49144af2$0$17068$6e1ede2f@read.cnntp.org...

Juha Nieminen wrote:

Jeff Schwab wrote:

template<typename T>
std::ostream& operator<<(std::ostream& out, std::vector<T> const& v) {
    if (!v.empty()) {
        typedef std::ostream_iterator<T> out_iter;
        copy(v.begin(), v.end() - 1, out_iter( out, " " ));
        out << v.back();
    }
    return out;
}


  Is there some advantage of that code over a shorter and simpler:

template<typename T>
std::ostream& operator<<(std::ostream& out, std::vector<T> const& v) {
    for(std::size_t i = 0; i < v.size()-1; ++i)


Nit: std::size_t is not guaranteed to be vector::size_type.


so could be
std::size_t != vector::size_type
and what could happen if in the definition
size_t sii=big;
int a[sii];
vector<int> b(a, a+sii);

        out << v[i] << " ";
    out << v.back();


I think, v.back() has undefined behavior if the v is empty.

    return out;
}


Best

Kai-Uwe Bux

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