reverse -- print reverse (background and foreground colors exchanged)

 

*** requires ncurses support compiled in ***
See Documentation/Advanced for info.

clear screen 
... 
print reverse "foo" 

reverse may be used to print text in reverse. reverse is not a seperate command, but part of the print-command; it may be included just after the print and can only be issued once that clear screen has been issued.

clear screen 

print "1 "
c=3 
do 
	prim=true 
	for a=2 to sqrt(c) 
		if (frac(c/a)=0) then 
			prim=false 
			break 
		endif 
	next a 
	if (prim) then 
		print 
		print reverse c; 
	else 
		print c; 
	endif 
	print " "
	c=c+1 
loop 

This program prints numbers from 1 on and marks each prime number in reverse.
Start this program in a terminal.