FreeBASIC GMPで階乗

'Factorial
'dodicat さんのユーザ定義関数を使う
'https://www.freebasic.net/forum/viewtopic.php?t=23225
'by dodicat ≫ Jan 17, 2015 1:11 

#Include "gmpFunctionsJP.bas"

Dim n As Integer

For n=1 To 35
   Print n; "! = "; factorial(n)
Next n

Print
Print "factorial(1000) = "; factorial(1000) 
Sleep

'Factorial

#include once "gmp.bi"

Dim n As Integer
Declare Function Kaijyou(n As Integer) As ULongInt
Declare Sub KaijyouGMP(n As Integer)

For n=1 To 25
   Print n; "! = "; Kaijyou(n)
   If n = 20 Then Print , "20! が 64 ビット符号なし型 の限界"
Next n

Print , "GMP を使うと(何かキー入力して下さい。)"
Sleep

KaijyouGMP(20)
KaijyouGMP(21)
KaijyouGMP(1000)

Sleep

Sub KaijyouGMP(n As Integer)
   
   Dim i As Integer 
   Dim As mpz_ptr BigNum = Allocate(SizeOf(__mpz_struct))
   
   mpz_init_set_si(BigNum, 1)
   
   For i = 1 to n
      mpz_mul_ui(BigNum, BigNum, i)
      'BigNum = BigNum * i
   Next i
   
   Print n; "! = ";
   Dim As ZString Ptr s = mpz_get_str(0, 10, BigNum)
   Print *s;
   Deallocate(s)
   Print
   
   mpz_clear(BigNum)
   Deallocate(BigNum)
End Sub

Function Kaijyou(n As Integer) As ULongInt
   Dim F As ULongInt
   Dim i As Integer
   F = 1
   For i = 1 to n
      F = F * i
   Next i
   Kaijyou = F
End Function