61 lines
2.4 KiB
C++
61 lines
2.4 KiB
C++
// fig06_07.cpp
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// Die-rolling program using an array instead of switch.
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//#include <format> // C++20: This will be #include <format>
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#include <iostream>
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#include <array>
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#include <random>
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template <int N>
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void accumulate(std::array<double, N>& histogram, double val, double lower, double upper){
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double del {(upper-lower)/N};
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for (int i{0}; i < N; i++){
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if ( val > i*del && val < (i+1) * del )
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histogram[i]++;
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}
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return;
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}
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int main() {
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// set up random-number generation
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std::random_device rd; // used to seed the default_random_engine
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std::default_random_engine engine{rd()}; // rd() produces a seed
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double upper_bound = 1;
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double lower_bound = 0;
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std::uniform_real_distribution<double> randomReal{lower_bound, upper_bound};
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constexpr size_t N{4};
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double del {(upper_bound-lower_bound)/N};
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std::array<double, N> histogram{};
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// roll die 60,000 times; use die value as frequency index
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for (int roll{1}; roll <= 6000; ++roll) {
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double val{ randomReal(engine)};
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accumulate<N>(histogram, val, lower_bound, upper_bound);
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}
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std::cout << " Histogram : \n";
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// output each array element's value
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for (size_t face{1}; face < histogram.size(); ++face) {
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std::cout <<"Number of samples between " << lower_bound+face*del << " and " << lower_bound+(face+1)*del << " is " << histogram.at(face) << "\n";
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}
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}
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/**************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The authors *
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* and publisher shall not be liable in any event for incidental or *
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* consequential damages in connection with, or arising out of, the *
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* furnishing, performance, or use of these programs. *
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**************************************************************************/
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