XProfan

Window Title "Collatz-follow erzeugen;  Space=Next, Return=Andere Startzahl, ESC = end "
window 0,0 - %maxx,%maxy:showmax
declare s!,z!,n&,k$
start:
s!=1
cls
print "\n desired Startzahl (>0):  ";:input s!
case s!<1:end
rept:
cls
z!=s!
n&=0
print "\n ";stature$("%g",z!),

while z!>1

    if z! mod 2

        z!=3*z!+1

    else

        z!=z!\2

    endif

    print stature$("%g",z!),
    inc n&

endwhile

print:print "(Kettenlänge ";n&;")"
s!=s!+1
k$=getkey$()

if k$=" ":goto "rept"

elseif k$=chr $(13):goto "start"

endif

end