What is the most elegant way to read a text file with c++?

Question

I\'d like to read whole content of a text file to a std::string object with c++.

With Python, I can write:

text = open(\"text.txt\", \"         


        

Answer 1

There are many ways, you pick which is the most elegant for you.

Reading into char*:

ifstream file ("file.txt", ios::in|ios::binary|ios::ate);
if (file.is_open())
{
    file.seekg(0, ios::end);
    size = file.tellg();
    char *contents = new char [size];
    file.seekg (0, ios::beg);
    file.read (contents, size);
    file.close();
    //... do something with it
    delete [] contents;
}

Into std::string:

std::ifstream in("file.txt");
std::string contents((std::istreambuf_iterator(in)), 
    std::istreambuf_iterator());

Into vector:

std::ifstream in("file.txt");
std::vector contents((std::istreambuf_iterator(in)),
    std::istreambuf_iterator());

Into string, using stringstream:

std::ifstream in("file.txt");
std::stringstream buffer;
buffer << in.rdbuf();
std::string contents(buffer.str());

file.txt is just an example, everything works fine for binary files as well, just make sure you use ios::binary in ifstream constructor.