I think that your problem is that precision() sets the precision used in future stream insertion operations, not when generating the final string to present. That is, by writing ta << a; tb << b; tc << c; ta.precision(2); tb.precision(2); tc.precision(2); You’re setting precision too late, as the first three lines have already converted the … Read more
I’ve always done: s.clear();//clear any bits set s.str(std::string()); @litb gets into more detail about how to seekp to the start of the stream combined with std::ends you can keep your allocated size.
std::ifstream has a method rdbuf(), that returns a pointer to a filebuf. You can then “push” this filebuf into your stringstream: #include <fstream> #include <sstream> int main() { std::ifstream file( “myFile” ); if ( file ) { std::stringstream buffer; buffer << file.rdbuf(); file.close(); // operations on the buffer… } } EDIT: As Martin York remarks … Read more
Another version… Use strtol, wrapping it inside a simple function to hide its complexity : inline bool isInteger(const std::string & s) { if(s.empty() || ((!isdigit(s[0])) && (s[0] != ‘-‘) && (s[0] != ‘+’))) return false; char * p; strtol(s.c_str(), &p, 10); return (*p == 0); } Why strtol ? As far as I love C++, … Read more
There’s history, which is disappointing. But also a future that looks bright. When move semantics went into C++11, it was huge, controversial, and overwhelming. I wanted to be able to move strings into and out of stringstream. However the politics at the time demanded that the internal store did not have to be a basic_string<charT>. … Read more
There’s no reason to expect std::string‘s appending functions to be slower than stringstream‘s insertion functions. std::string will generally be nothing more than a possible memory allocation/copy plus copying of the data into the memory. stringstream has to deal with things like locales, etc, even for basic write calls. Also, std::string provides ways to minimize or … Read more
From this reference: If extraction fails (e.g. if a letter was entered where a digit is expected), value is left unmodified and failbit is set (until C++11) If extraction fails, zero is written to value and failbit is set. If extraction results in the value too large or too small to fit in value, std::numeric_limits::max() … Read more
Copying of ANY stream in C++ is disabled by having made the copy constructor private. Any means ANY, whether it is stringstream, istream, ostream,iostream or whatever. Copying of stream is disabled because it doesn’t make sense. Its very very very important to understand what stream means, to actually understand why copying stream does not make … Read more
You can use tandem of MemoryStream and StreamReader classes: void Main() { string myString; using (var stream = new MemoryStream()) { Print(stream); stream.Position = 0; using (var reader = new StreamReader(stream)) { myString = reader.ReadToEnd(); } } }
C++03 std::string s; for (std::vector<std::string>::const_iterator i = v.begin(); i != v.end(); ++i) s += *i; return s; C++11 (the MSVC 2010 subset) std::string s; std::for_each(v.begin(), v.end(), [&](const std::string &piece){ s += piece; }); return s; C++11 std::string s; for (const auto &piece : v) s += piece; return s; Don’t use std::accumulate for string concatenation, … Read more