C++ Programming :: How can I read 2 characters from file into a std::string


	How can I read 2 characters from file into a std::string How can I read in two characters from a file into a std::string? the long way: fstream f("myfile.bin", ios::binary \| ios:in); // Opened for read binary... unsigned char buffer[3]; buffer[2] = '\0'; f.read(buffer, 2); std::string x(buffer); Got a better way? SpreadTooThin wrote: > How can I read in two characters from a file into a std::string? > the long way: > fstream f("myfile.bin", ios::binary \| ios:in); // Opened for read binary... > unsigned char buffer[3]; > buffer[2] = '\0'; > f.read(buffer, 2); > std::string x(buffer); > Got a better way? fstream f("myfile.bin", ios::binary \| ios:in); char buffer[2]; f.read(buffer, 2); std::string x(buffer, buffer+2); They do behave differently. On Jun 6, 10:11 pm, SpreadTooThin <bjobrie@gmail.com> wrote: > How can I read in two characters from a file into a std::string? > the long way: > fstream f("myfile.bin", ios::binary \| ios:in); // Opened for read > binary... > unsigned char buffer[3]; > buffer[2] = '\0'; > f.read(buffer, 2); > std::string x(buffer); > Got a better way? std::string x ; x += f.get() ; x += f.get() ; (Of course, you'll want to check that you actually did get two characters.) Something that will work with all current implementations, and will be guaranteed by the next version of the standard: std::string x( 2, ' ' ) ; f.read( &x[ 0 ], 2 ) ; -- James Kanze (GABI Software) email:james.ka@gmail.com Conseils en informatique oriente objet/ Beratung in objektorientierter Datenverarbeitung 9 place Smard, 78210 St.-Cyr-l'cole, France, +33 (0)1 30 23 00 34 James Kanze wrote: ... > Something that will work with all current implementations, and > will be guaranteed by the next version of the standard: Do you have a reference to the this proposal (contiguous strings)? On 2007-06-07 01:59:03 -0700, Gianni Mariani <gi3nos@mariani.ws> said: > James Kanze wrote: > ... >> Something that will work with all current implementations, and >> will be guaranteed by the next version of the standard: > Do you have a reference to the this proposal (contiguous strings)? See: http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530 -- Clark S. Cox III clarkc@gmail.com On Jun 7, 10:59 am, Gianni Mariani <gi3nos@mariani.ws> wrote: > James Kanze wrote: > ... > > Something that will work with all current implementations, and > > will be guaranteed by the next version of the standard: > Do you have a reference to the this proposal (contiguous strings)? It's in the current draft (N2134): "The char-like objects in a basic_string object shall be stored contiguously. That is, for any basic_string object s, the identity &(s.begin() + n) == &s.begin() + n shall hold for all values of n such that 0 <= n < s.size()." From what I understand, a non-const version of data() will also be added (as well as const and non-const data() functions to std::vector), in order to obtain the address in a way somewhat more transparently than &s[0]. -- James Kanze (GABI Software) email:james.ka@gmail.com Conseils en informatique oriente objet/ Beratung in objektorientierter Datenverarbeitung 9 place Smard, 78210 St.-Cyr-l'cole, France, +33 (0)1 30 23 00 34 James Kanze wrote: > It's in the current draft (N2134) Just so everyone's up to date, the current draft (reflecting changes made at the April, 2007 meeting) is N2284. -- -- Pete Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The Standard C++ Library Extensions: a Tutorial and Reference." (www.petebecker.com/tr1book)