c-resources/CPlusPlus20ForProgrammers-master/examples/ch06/fig06_07.cpp

// fig06_07.cpp
// Die-rolling program using an array instead of switch.
//#include <format> // C++20: This will be #include <format>
#include <iostream>
#include <array>
#include <random>

int main() {
   // set up random-number generation
   std::random_device rd; // used to seed the default_random_engine
   std::default_random_engine engine{rd()}; // rd() produces a seed 
   std::uniform_int_distribution randomDie{0, 6};

   std::uniform_real_distribution<double> randomReal{0, 1};

   constexpr size_t arraySize{7}; // ignore element zero
   std::array<int, arraySize> frequency{}; // initialize to 0s


   constexpr size_t N{7};
   std::array<double, N> histogram{};

   // roll die 60,000,000 times; use die value as frequency index
   for (int roll{1}; roll <= 60'000'000; ++roll) {
       randomReal(engine);
   }

   std::cout <<  "Face " <<  " Frequency  \n";

   // output each array element's value
   for (size_t face{1}; face < histogram.size(); ++face) {
      std::cout << face << " " << histogram.at(face) << "\n";
   }
}

/**************************************************************************
 * (C) Copyright 1992-2022 by Deitel & Associates, Inc. and               *
 * Pearson Education, Inc. All Rights Reserved.                           *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 **************************************************************************/