To print the output from a C++ program running in a DOS environment, redirect the output to a text file using the command "myprogram.exe > result.txt" and then print the file using "print result.txt" or by double-clicking the file and selecting print. An alternative method mentioned is redirecting output directly to a printer using "myprogram.exe > prn" or "myprogram.exe > lpt1", although compatibility may vary, especially in DOSBox. For networked printing, users can share a printer and connect it to LPT1 using the command "net use lpt1: \\mymachine\myprinter", allowing direct printing even from USB-connected printers.