ankit.tayal560 - type start /? in a windows command prompt for more information on what marto is trying to impart.
basically there are 3 ways to start new processes in perl:
- open - open (IN, "program.exe|") or die "couldn't start program.exe"
- system - system('program.exe')
- backticks or qx - qx(program.exe) or `program.exe`
careful what you do when running programs that require external input from users, but in a nutshell what's happinging in system('start "" "' . $calc . '"'); is the same as system('program.exe arg1');