classes overload the operators >> for reading from a file and << for writing to it. There are several overloaded versions for each operator, one for each built-in type. In addition, these operators support several user-defined types, including std::string. You can use these operators for reading and writing data to a file. The following function reads all the words in a text file into a string using << and stores each retrieved string in a vector:

 #include #include using namespace std;int main(){ ifstream ftext; string word; vector  vs; ftext.open("data.txt"); if (!ftext)   exit (-1); while (ftext>>word) // as long as sizeof hasn't been reached {  vs.push_back(word); //copy word to vector }}