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What is the best way to slurp a file into a std::string in c++?
I assumed there would be a question like this already, but I couldn't find one. So here goes my question.
What is the shortest way to read a whole text file into a string? I only want to use features of the newest C++ standard and standard libraries.
I think there must be an one liner for this common task!
Probably this:
std::ifstream fin("filename"); std::ostringstream oss; oss << fin.rdbuf(); std::string file_contents = oss.str(); There's also this:
std::istreambuf_iterator<char> begin(fin), end; std::string file_contents(begin, end); Some might suggest this, but I prefer to type istreambuf_iterator<char> only once.
std::string file_contents(std::istreambuf_iterator<char>{fin}, std::istreambuf_iterator<char>()); 
To read a file into a std::string using one statement (whether it fit on one line depends on the length of you lines...) looks like this:
std::string value{ std::istreambuf_iterator<char>( std::ifstream("file.txt").rdbuf()), std::istreambuf_iterator<char>()}; The approach is unfortunately often not as fast as using an extra std::ostringstream is (although it should really be faster...).
