I have a function that reads through an istringstream and does some operations on it so ... I am trying to read in a file using fstream and convert the fstream object to an istringstream in order to pass it to my function. I don't know how to do this. Any help would be much appreciated. I am still pretty much a beginner so please keep it simple if you can.
string inputFile(argv[1]);
ifstream inFile(inputFile.c_str());
istringstream is;
is >> inFile.rdbuf(); //*******This is wrong and is what I'm having trouble with
function(is);
What you want is std::istream_iterator:
std::string myString ( std::istream_iterator(inputFile) , std::istream_iterator() ) ;
std::istringstream is ( myString ) ;
This creates a string with the contents of inputFile by using a begin iterator (std::istream_iterator(inputFile)) and an end iterator (std::istream_iterator()). It then creates an istringstream from that string.
This solves your immediate problem, but there is almost certainly a better way to do what you are trying to do. For example:
Pass an istream instead of an istringstream (because then you don't have to copy it).
Change your algorithm to not need an istringstream.