Quote from: salieri on November 23, 2017, 08:15:26 PM

//**********************************************
// Online C++ Compiler.
// https://www.onlinegdb.com/online_c++_compiler
//**********************************************

#include
#include /* round */

using namespace std;

int main()
{
   unsigned int MagicNumber, RolledNumber;
   double dTemp;

   MagicNumber = 4294752547;

   printf("\n Rounding Decimals to the Nearest Whole Number.");

   // #0
   dTemp = (double) (MagicNumber - 1) / 429496.7295;
   RolledNumber = (unsigned int)round(dTemp);
   printf("\n MagicNumber - 1 = %lu, dTemp = %.08f, RolledNumber = %lu.", MagicNumber - 1, dTemp, RolledNumber);

   // #1 (success)
   dTemp = (double) MagicNumber / 429496.7295;
   RolledNumber = (unsigned int)round(dTemp);
   printf("\n MagicNumber = %lu, dTemp = %.08f, RolledNumber = %lu.", MagicNumber, dTemp, RolledNumber);

   // 2^32 = 4294967295 + 1, 4294967295 - 4294752547 + 1 = 214749.
   printf("\n Conclusion. There are only 214749 numbers for which a rolled number will be 10000.");
   printf("\n The first suitable number is %lu.", MagicNumber);
   printf("\n WIN CHANCE is %.06f %% per each roll.", 214749.0/4294967295.0 * 100.0);

   return 0;
}

Output:
Rounding Decimals to the Nearest Whole Number.
MagicNumber - 1 = 4294752546, dTemp = 9999.49999852, RolledNumber = 9999.
MagicNumber = 4294752547, dTemp = 9999.50000085, RolledNumber = 10000.
Conclusion. There are only 214749 numbers for which a rolled number will be 10000.
The first suitable number is 4294752547.
WIN CHANCE is 0.005000 % per each roll.

What is this?