Define a function called copy_line that takes one argument that is an input stream. When called, copy_line reads one line of input from the input stream given as its argument and writes that line to the screen. You shouldbe able to call your function using either cin or an input-file stream as the argument to your function copy_line. (If the argument is an input-file stream, then the stream is connected to a file before the function is called, so copy_line will not open or close any files.) For example, the first of the following two calls to copy_line will copy a line from the file stuff.dat to the screen, and the second will copy a line from the keyboard to the screen:

ifstream fin;

fin.open("stuff.dat");

copy_line(fin);

copy_line(cin);