Все Первая цифра числа

Dim $aValue[10] = [1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800]

For $i = 0 To Ubound($aValue) - 1
    ConsoleWrite(Left($aValue[$i], 100) & @CRLF)
Next

Func Left($aNumber, $iLimit)
	If $aNumber >= $iLimit And $aNumber <= 5000 Then
	    If Not IsFloat($aNumber / 2) Then
	        Return StringLeft($aNumber, 1)
	    Else
            Return $aNumber	
	    EndIf
	EndIf
EndFunc

For $i = 1 To 200
	If $i >= 100 Then
	    ConsoleWrite(Factorial($i) & @CRLF)
	EndIf	
Next	

Func Factorial($aNumber)
    Local $aRet
    If ($aNumber = 0) Or ($aNumber = 1) Then Return 1	
    For $i = 1 to $aNumber
        $aRet += Log($i) / Log(10)
    Next
    If $aNumber <= 170 Then $aRet = 10 ^ $aRet
    Return StringLeft($aRet, 1)
EndFunc

Dim $Array[10] = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10']

For $x = 0 To UBound($Array) - 1
	ConsoleWrite(StringMid(Factorial($Array[$x]), 1, 1) & @CRLF)
Next

Func Factorial($mfFactor)
	If Not (StringIsInt($mfFactor)) OR (Int($mfFactor) < 0) Then
		SetError(1)
		Return 0
	Else
		$mfFactor = Int($mfFactor)
	EndIf
	If $mfFactor = 0 Then Return 1
	Dim $return = 1
    For $i = $mfFactor to 1 Step - 1
        $return *= $i
    Next
	Return $return
EndFunc

#include <MathEx.au3>

Dim $Array[10] = [121, 157, 189, 210, 250, 290, 310, 347, 377, 400]

For $x = 0 To UBound($Array) - 1
	ConsoleWrite(StringMid(_Factorial($Array[$x]), 2, 1) & @CRLF)
Next

#include "BigNum.au3"
$iT = TimerInit()
$iF = 1
$iN = 5001
If $iN < 0 Then Exit 99 * 0 + ConsoleWrite("Число : " & $iN & @CR & "Факториал : 0" & @CR & "Первая Цифра : 0" & @CR & "Время : " & TimerDiff($iT) & @CR)
If $iN = 0 Then Exit 99 * 0 + ConsoleWrite("Число : " & $iN & @CR & "Факториал : 1" & @CR & "Первая Цифра : 1" & @CR & "Время : " & TimerDiff($iT) & @CR)

For $i = 1 To $iN
	$iF = _BigNum_Mul($iF, $i)
Next
ConsoleWrite("Число : " & $iN & @CR & "Факториал : " & $iF & @CR & "Первая Цифра : " & StringLeft($iF, 1) & @CR & "Время : " & TimerDiff($iT) & @CR)

#include "BigNum.au3"
MsgBox(0, '', _Fl(100))

Func _Fl($n)
	$r='1'
	For $i = 2 To $n
		$r &= '*'&$i
	Next
	Return _BigNum_Parse($r)
EndFunc

#include <Date.au3>

ConsoleWrite(" старт " & _NowTime() & @CRLF )
ConsoleWrite("первая цифра = " & StringLeft(_eshe_parocku(5001),1) & @CRLF )
ConsoleWrite(" стоп " & _NowTime() & @CRLF )

Func _eshe_parocku($aNumber)
    Local $aRet = 1
	For $i = 1 to $aNumber
        $aRet *= $i
		If $aRet > 10000000 Then $aRet = Floor($aRet / 1000)
    Next
	Return $aRet
EndFunc

$total_my = 0
$total = 0
$NTry = 1000

For $i = 1 to $NTry
	$N = Random(4000, 5000, 1)
	$start = TimerInit()
	FirstDigit($N)
	$total_my += TimerDiff($start)
	$start = TimerInit()
	C2H5OH($N)
	$total += TimerDiff($start)
Next
ConsoleWrite('Average time of my method:' & @TAB & @TAB & $total_my/$NTry & ' msecs' & @CRLF)
ConsoleWrite('Average time of other method:' & @TAB & $total/$NTry & ' msecs' & @CRLF)

Func FirstDigit($N)
	$S = 0
	For $i = 1 to $N
		$S += Log10($i)
	Next
	Return Floor(10^Mod($S, 1))
EndFunc

Func Log10($N)
	Return Log($N)/Log(10)
EndFunc

Func C2H5OH($aNumber)
    Local $aRet = 1
    For $i = 1 to $aNumber
        $aRet *= $i
        If $aRet > 10000000 Then $aRet = Floor($aRet / 1000)
    Next
    Return StringLeft($aRet, 1)
EndFunc