Displaying an error message if a file can't be opened, C++

Question

I'm using fstream to open up .txt files with C++. So far it's working great. However, I'd like my console to display an error message if the input_file can't be opened. How should I go about this?

Snippet:

cin >>  in_file_name ;

ifstream in_file(in_file_name.c_str());

in_file_str.assign(istreambuf_iterator<char>(in_file), 
istreambuf_iterator<char>());

Answer 1

ifstream in_file(in_file_name.c_str());
if( in_file.fail() ) {
    cerr << "Error!" << endl;
}

Answer 2

Use fail() to determine whether the ifstream was successfully opened or not.