Question:
When I run the following program:

#include main(){fstream printer1;printer1.open(“prn”, ios::out);printer1 << "Hello World";}

the output never makes it to the printer. What am I doing wrong?

Answer:
When it comes to external devices like printers, etc., there could be a dozenproblems that prevent it from printing.

Assuming that on your platform there is a predefined file called “prn” thatwill cause output to your printer, assuming that is true and alsoassuming that your printer is connected correctly and configured well,the only reason I can think of is that the stream implementation is buffered and requires an explicit flush to work (see example below).

Also, make sure that the program is not creating a file under the currentdirectory named “prn”; if this is so, your platform does not treat thefilename “prn” in any special way.

#include main(){	fstream printer1;	printer1.open(“prn”, ios::out);	printer1 << "Hello World" << flush;}

Hope that helps.