fig06_07.cpp

// fig06_07.cpp
// Die-rolling program using an array instead of switch.
#include <fmt/format.h> // 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{1, 6};

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

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

   std::cout << fmt::format("{}{:>13}\n", "Face", "Frequency");

   // output each array element's value
   for (size_t face{1}; face < frequency.size(); ++face) {
      std::cout << fmt::format("{:>4}{:>13}\n", face, frequency.at(face));
   }
}

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