lst-0003-book.cpp
void process(const vector<string>& args) {
if(args.size() == 0) { // expect parameters
throw std::invalid_argument{"Command line argument missing"};
} else {
for(const string filename : args) {
cout << filename << ": ";
try {
cout << countWords(filename) << "\n";
} catch(std::exception &exc) {
cout << "Error: " << exc.what() << "\n";
}
}
}
}