.. _example-of-using-pseudorandom-number-generation-functions:


Example of Using Pseudorandom Number Generation Functions
=========================================================


.. container:: example
   :name: EX5-6


   .. rubric:: Find Pseudorandom Co-primes
      :class: sectiontitle

   .. code-block:: cpp


      void FindCoPrimes(void){ 
         int size; 
        

         // define Pseudo Random Generator (default settings) 
         ippsPRNGGetSize(&size); 
         IppsPRNGState* pPrng = (IppsPRNGState*)(new Ipp8u [size] ); 
         ippsPRNGInit(160, pPrng); 
        

         // define 256-bits Big Numbers X and Y 
         const int bnBitSize = 256; 
         IppsBigNumState* bnX = New_BN(bnBitSize/32); 
         IppsBigNumState* bnY = New_BN(bnBitSize/32); 
        

         // define temporary Big Numbers GCD and 1 
         IppsBigNumState* bnGCD = New_BN(bnBitSize/32); 
         Ipp32u one = 1; 
         IppsBigNumState* bnOne = New_BN(1, &one); 
        

        

         // generate pseudo random X and Y 
         // while GCD(X,Y) != 1 
         Ipp32u result; 
         int counter; 
         for(counter=0,result=1; result; counter++) { 
            ippsPRNGen_BN(bnX, bnBitSize, pPrng); 
            ippsPRNGen_BN(bnY, bnBitSize, pPrng); 
            ippsGcd_BN(bnX, bnY, bnGCD); 
            ippsCmp_BN(bnGCD, bnOne, &result); 
         } 
        

         cout <<"Coprimes:" <<endl; 
         Type_BN("X: ", bnX); cout <<endl; 
         Type_BN("Y: ", bnY); cout <<endl; 
         cout <<"were fond on " <<counter <<" attempt" <<endl; 
        

         delete [] (Ipp8u*)pPrng; 
         delete [] (Ipp8u*)bnX; 
         delete [] (Ipp8u*)bnY; 
         delete [] (Ipp8u*)bnGCD; 
         delete [] (Ipp8u*)bnOne; 
      }