[kust]

Fig. 6.7 | Die-rolling program using an array instead of switch.
// fig06_07.cpp
// Die-rolling program using an array instead of switch.
#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 << std::format("{}{:>13}\n", "Face", "Frequency");
   
   // output each array element
   for (size_t face{1}; face < frequency.size(); ++face) {
      std::cout << std::format("{:>4}{:>13}\n", face, frequency.at(face));
   }
}