# TITLE:  Factoring by Reverse Trial Division     
# AUTHOR: Roy Maclean 
# EMAIL:  rfamgm at gmail
# WEB:    http://www.spiderpixel.co.uk/caspro        
# DATE:   15Jan1998       
# MAKE:   CASIO
# MODEL:  fx6300G or greater
# SIZE:   124
# NOTES:  Enter a positive integer. The prime factors will be displayed.
#         This uses trial division starting from the sqrt(n) downwards.


@@ Program "REVTRIAL"

Lbl 0
?->A:Goto 2
Lbl 1
2_
A/2->A:A=1=>Goto 0
Lbl 2
Frac .5A=0=>Goto 1
Int sqrt(A)->B
Frac sqrt(A)<>0=>1+B->B
Frac .5B=0=>1+B->B
Lbl 4
B<=1=>Goto 6
Frac (A/B)=0=>Goto 5
B-2->B:Goto 4
Lbl 5:B_
A/B->B:Goto 3
Lbl 6:A