POV-Ray : Newsgroups : povray.newusers : Prime numbers : Re: Prime numbers Server Time
14 Aug 2022 03:41:28 EDT (-0400)
  Re: Prime numbers  
From: kurtz le pirate
Date: 22 Jan 2022 13:25:21
Message: <61ec4c11$1@news.povray.org>
On 13/01/2022 21:30, Cabesa wrote:
> Now, this is quite a simple request- but I ve been unable to do so myself and
> have no idea how to accomplish it.
> Let me explain:
> 
> I have a ".txt" file, with a random number. The idea is to debug a message that
> states whether said number is prime or not. Now,this should be quite an easy
> task, but i dont seem to wrap my head around it and dont know witch "ifs" or
> "whiles" to put so that the programme knows if the number meets with the
> condition.
> 
> Thanks in advance (for those that read this far)
> 

It's not the best way to do it, but it's done in 5mn ... ;)


// -----------------------------------------------------------
// --- unitary test
// -----------------------------------------------------------
#declare num = 98452;
#declare cnt = 0;
#declare i=2;
#while(i<num)
 #if (mod(num,i)=0)
  #declare cnt=cnt+1;
 #end
 #declare i=i+1;
#end
#debug concat(str(num,0,0)," is ")
#if(cnt !=0 )
 #debug "not a prime number\n"
#else
 #debug "a prime number\n"
#end
#debug "\n\n------------\n\n"



// -----------------------------------------------------------
// --- find prime numbers between 0 and ...
// -----------------------------------------------------------
#declare num=0;
#while(num<50)
 #declare cnt = 0;
 #declare i=2;
 #while( i < num)
  #if (mod(num,i)=0)
   #declare cnt=cnt+1;
  #end
  #declare i=i+1;
 #end
 #if(cnt =0 )
  #debug concat("prime number ",str(num,0,0),"\n")
 #end
 #declare num=num+1;
#end
#debug "\n\n------------\n\n"




// -----------------------------------------------------------
// --- macro to test if a it is a prime numbers
// -----------------------------------------------------------
#macro IsPrime(n)
 #local cnt = 0;
 #local i=2;
 #while(i<n)
  #if(mod(n,i)=0)
   #declare cnt=cnt+1;
  #end
  #declare i=i+1;
 #end
 (cnt=0)
#end



// -----------------------------------------------------------
// --- test a number using the macro
// -----------------------------------------------------------
#declare a = 51286;
#debug concat("Is ",str(a,0,0)," a prime number ? ")
#if(IsPrime(a))
  #debug "yes\n"
#else
  #debug "no\n"
#end

#declare a = 51287;
#debug concat("Is ",str(a,0,0)," a prime number ? ")
#if(IsPrime(a))
  #debug "yes\n"
#else
  #debug "no\n"
#end

#declare a = 51288;
#debug concat("Is ",str(a,0,0)," a prime number ? ")
#if(IsPrime(a))
  #debug "yes\n"
#else
  #debug "no\n"
#end
#debug "\n\n------------\n\n"






-- 
Kurtz le pirate
Compagnie de la Banquise


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