[bmx] Twin Primes by daaan [ 1+ years ago ]

[BlitzBot]

Title : Twin Primes
Author : daaan
Posted : 1+ years ago

Description : I had a assembly programming assignment that was to print out the first 100 twin primes. So I made this mock up program to figure how a easy method for calculating twin primes. It does in fact work, but now I need to translate it into assembly

Code :

Code (blitzmax) Select Expand

Rem
**********************************************************
twin primes by daniel wooden
**********************************************************
End Rem

Local count:Int = 1
Local curnum:Int = 3

Local a:Int = 0
Local b:Int = 0

While count < 101 ' <-- twin primes upto the 100th place.

If IsPrime( curnum ) And IsPrime( curnum+2 ) Then
a = curnum
b = curnum+2
Print "Twin Prime Set: " + count + " (" + a + "," + b + ")"
count :+ 1
End If

curnum :+ 1

Wend
End

Function IsPrime:Int( Num:Int )

Local Prime:Int = True

For i = 2 To Num/2
If (Num Mod i) = 0 Then
Prime = False
End If
Next

Return Prime

End Function

Comments :


rdodson41(Posted 1+ years ago)

 Your calculating the even numbers too, try curnum :+ 2, should go twice as fast.


Azathoth(Posted 1+ years ago)

 To make IsPrime faster you should use 'Exit' after 'Prime = False' because you're still in the 'For-Next' loop when using large numbers.


ShadowTurtle(Posted 1+ years ago)

 compatible without blitzmax:

Code Select Expand

;**********************************************************
;twin primes by daniel wooden
;converted by shadowturtle
;**********************************************************


Local count = 1
Local curnum = 3

Local a = 0
Local b = 0

While count < 101

If IsPrime( curnum ) And IsPrime( curnum+2 ) Then
a = curnum
b = curnum+2
Print "Twin Prime Set: " + count + " (" + a + "," + b + ")"
count = count + 1
End If

curnum = curnum + 1

Wend
WaitKey
End

Function IsPrime( Num )

Local Prime = True

For i = 2 To Num/2
If (Num Mod i) = 0 Then
Prime = False
End If
Next

Return Prime

End Function