Actually, IOStreams don’t have to be slow! It is a matter of implementing them in a reasonable way to make them fast, though. Most standard C++ library don’t seem to pay too much attention to implement IOStreams. A long time ago when my CXXRT was still maintained it was about as fast as stdio – … Read more
You can open the file using the ios::ate flag (and ios::binary flag), so the tellg() function will directly give you directly the file size: ifstream file( “example.txt”, ios::binary | ios::ate); return file.tellg();
IOstreams use streambufs to as their source / target of input / output. Effectively, the streambuf-family does all the work regarding IO and the IOstream-family is only used for formatting and to-string / from-string transformation. Now, istream_iterator takes a template argument that says what the unformatted string-sequence from the streambuf should be formatted as, like … Read more
Here’s a non-deprecated method found on the web, has you derive your own std::streambuf class, but easy and seems to work: #include <iostream> #include <istream> #include <streambuf> #include <string> struct membuf : std::streambuf { membuf(char* begin, char* end) { this->setg(begin, begin, end); } }; int main() { char buffer[] = “I’m a buffer with embedded … Read more
Why does this happen? This has little to do with the input you provided yourself but rather with the default behavior std::getline() has. When you provided your input for the age (std::cin >> age), you not only submitted the following characters, but also an implicit newline was appended to the stream when you typed Enter: … Read more