This is one of my favorite tuck-away functions I keep on hand for multiple uses. #include <sys/stat.h> // Function: fileExists /** * Check if a file exists * * @param[in] filename – the name of the file to check * * @return true if the file exists, else false */ bool fileExists(const std::string& filename) { … Read more
Of course there is. Just use reference. Like that: void foo (std::ofstream& dumFile) {} Otherwise the copy constructor will be invoked, but there is no such defined for the class ofstream.
As @Mgetz says, you probably forgot to #include <fstream>. The reason you didn’t get a not declared error and instead this incomplete type not allowed error has to do with what happens when there is a type that has been “forward declared”, but not yet fully defined. Look at this example: #include <iostream> struct Foo; … Read more
std::ofstream fout(“vector.txt”); fout << std::setprecision(10); for(auto const& x : vector) fout << x << ‘\n’; Everything I changed had theoretically worse performance in your version of the code, but the std::endl was the real killer. std::vector::at (with bounds checking, which you don’t need) would be the second, then the fact that you did not use … Read more
You can do this, which doesn’t need to create the string. It makes the output stream read out the contents of the stream on the right side (usable with any streams). outFile << ss.rdbuf();
I think the previous answers are misleading. fstream is a proper RAII object, it does close automatically at the end of the scope, and there is absolutely no need whatsoever to call close manually when closing at the end of the scope is sufficient. In particular, it’s not a “best practice” and it’s not necessary … Read more
First, make an ifstream: #include <fstream> std::ifstream infile(“thefile.txt”); The two standard methods are: Assume that every line consists of two numbers and read token by token: int a, b; while (infile >> a >> b) { // process pair (a,b) } Line-based parsing, using string streams: #include <sstream> #include <string> std::string line; while (std::getline(infile, line)) … Read more