std::vector to string with custom delimiter

Question

I would like to copy the contents of a vector to one long string with a custom delimiter. So far, I've tried:

// .h string getLabeledPointsString(const string delimiter=","); // .cpp string Gesture::getLabeledPointsString(const string delimiter) {     vector<int> x = getLabeledPoints();     stringstream  s;     copy(x.begin(),x.end(), ostream_iterator<int>(s,delimiter));     return s.str(); } 

but I get

no matching function for call to ‘std::ostream_iterator<int, char, std::char_traits<char> >::ostream_iterator(std::stringstream&, const std::string&)’ 

I've tried with charT* but I get

error iso c++ forbids declaration of charT with no type 

Then I tried using char and ostream_iterator<int>(s,&delimiter) but I get strange characters in the string.

Can anyone help me make sense of what the compiler is expecting here?

Answer 1

Use delimiter.c_str() as the delimiter:

copy(x.begin(),x.end(), ostream_iterator<int>(s,delimiter.c_str())); 

That way, you get a const char* pointing to the string, which is what ostream_operator expects from your std::string.

Answer 2

C++11:

vector<string> x = {"1", "2", "3"}; string s = std::accumulate(std::begin(x), std::end(x), string(),                                 [](string &ss, string &s)                                 {                                     return ss.empty() ? s : ss + "," + s;                                 });