ifstream

I have code that currently does something like the following: ofstream fout; fout.open("file.txt"); fout<<"blah blah "<<100<<","<<3.14; //get ofstream length here fout<<"write more stuff"<<endl; Is there a convenient way to find out the length of that line that is written at the stage I specified above? (in real life, the int 100 and float 3.14 are not constant and can change). Is there a good way to do what I want? EDIT: by length, I mean something that can be used using fseek, e.g. fseek(pFile, -linelength, SEEK_END); You want tellp . This is available for output streams (e.g., ostream,

My professor is very smart but expects complete noobs like me to just know how to program c++ . I don't understand how the fstream function works. I will have a data file with three columns of data. I will have to determine with a logarithm whether each line of data represents a circle, rectangle or triangle - that part is easy. The part I don't understand is how the fstream function works. I think I: #include < fstream > then I should declare my file object? ifstream Holes; then I open it: ifstream.open Holes; // ? I don't know what the proper syntax is and I can't find straightforward

The following program demonstrates an inconsistency in std::getline behavior between libc++ and libstdc++ (using clang3.3). The program opens the file testfile, reads it until eof, then clears the error bits using ifstream::clear and tries to read from the same filehandle again to see if new data was appended to the file. #include <fstream> #include <iostream> #include <unistd.h> using namespace std; int main() { ifstream* file = new ifstream("testfile"); if ( ! file->is_open() ) { cout << "testfile does not exist" << endl; return -1; } while ( 1 ) { file->clear(); // remove end of file evil

For this program i have only used field separators from data files in shell script. But I am trying to use the standard library function ifstream() to read in from a data file. The only problem is I am getting the data like so A:KT5:14:executive desk: This is for a hash table, and I need to separate the values in the line for the data structure as well as the transaction type. I’ve been looking around the web and have not found much on field separators and what I have found was quite confusing. The question then being, is there a way to set a field separator with the ifstream function or is

I tried to read a 3GB data file using ifstream and it gives me wrong file size, whereas when I read a 600MB file, it gives me the correct result. In addition to wrong file size, I am also unable to read the entire file using ifstream. Here is the code that I used std::wstring name; name.assign(fileName.begin(), fileName.end()); __stat64 buf; if (_wstat64(name.c_str(), &buf) != 0) std::cout << -1; // error, could use errno to find out more std::cout << " Windows file size : " << buf.st_size << std::endl;; std::ifstream fs(fileName.c_str(), std::ifstream::in | std::ifstream::binary); fs.seekg(0,

Seekg does not seem to work, when I reach EOF in myFile. ifstream myFile("/path/file"); for(int i; i < 10; i++){ myFile.seekg(0);//reset position in myFile while(getline(myFile, line)){ doSomething } } So, now I am opening input stream every loop: for(int i; i < 10; i++){ ifstream myFile("/path/file");//reset position in myFile while(getline(myFile, line)){ doSomething } } But I would rather seek to position 0. How can I achieve that? Joseph Mansfield Make sure you clear the error flags before the call to myFile.seekg() : myFile.clear(); After the EOF flag has ben set, you will not be able to