// ./tc factor.6.2.tc -r 'debug(1)'

// supports larger numbers

[
H:\>tc factor.6.2.tc -r main(0)
***  TINY-C VERSION 1.0,  COPYRIGHT 1977, T A GIBSON  ***
        This C version copyright 2017, T A Gibson

2020-02-13 07:45:20

factor.tc - 2/13/20 - lrb - source code has 1647 bytes

Enter number to factor 235039561
 15331 15331 = 235039561

2020-02-13 07:52:55
]

// 1947545161 = 44131*44131 (supported but would take a very long time)

// added time reporting

size [
 char foo(3000)
 return readfile"factor.6.2.tc",foo,3000
 ]

main int dbg [
 char datebuff(30);cdate datebuff;printf"%c%s%c",10,datebuff,10
 printf"%cfactor.tc - 2/13/20 - lrb - source code has %d bytes%c",10,size(),10
 int f,p(5000),idx,j,pc,sw,ft;ft=1
 p(0)=2;p(1)=3;idx=1;pc=5 // pc is a prime candidate
 pl"Enter number to factor ";f=gn
 while f%2==0 [pn 2;f=f/2;ft=ft*2]
 while f%3==0 [pn 3;f=f/3;ft=ft*3]
 while 1 [
  if dbg [
   printf"%cdebug idx = %d p(%d) = %d",10,idx,idx,p(idx)
   printf" pc = %d f = %d%c",pc,f,10
   ]
  // exit if we got 'em all 
  if f==1 [printf" = %d%c",ft,10;cdate datebuff;printf"%c%s%c",10,datebuff,10;abort]
  // is what's left prime? if yes, print and exit
  if pc*pc>f [pn f;ft=ft*f;printf" = %d%c",ft,10;cdate datebuff;printf"%c%s%c",10,datebuff,10;abort]
  sw=0;j=0
  while p(j)<p(idx) [ // try all smaller primes
   if pc%p(j)==0 [sw=1;break]
   j=j+1
   ] // while p(j)<p(idx)
  if sw==0 [ // new prime found
   idx=idx+1;p(idx)=pc // update prime array
   // divide out if it's a factor
   while f%pc==0 [pn pc;f=f/pc;ft=ft*pc]
   ] // if sw==0
  pc=pc+2 // next candidate
  ] // while 1
 ] // main

debug int dbg [
 main dbg
 ]