#include <iostream> #include <fstream> int main( int argc, char *argv[] ) { if ( argc != 2 ) { cout << "Usage: my_program filename" << endl; return 0; } ifstream inFile( argv[1] ); if ( !inFile ) { cerr << argv[1] << "could not be opened" << endl; return -1; } // and so on...Consult any book on C++ (or C), for instance Deitel and Deitel, C++ How to Program, for more details.