histogram.ccp was added.

CPlusPlus20ForProgrammers-master/examples/ch06/fig06_07.cpp

@@ -5,13 +5,25 @@
 #include <array>
 #include <random>
 
+template <int N>
+void accumulate(std::array<double, N>& histogram, double val, double upper, double lower){
+
+	double del {(upper-lower)/N};
+	for (int i{0}; i < N; i++){
+		if ( val > i*del && val < (i+1) * del )
+			histogram[i]++;
+	}
+	return;
+}
+
 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};
+   double upper_bound = 1;
+   std::uniform_real_distribution<double> randomReal{0, upper_bound};
 
    constexpr size_t arraySize{7}; // ignore element zero
    std::array<int, arraySize> frequency{}; // initialize to 0s
@@ -22,9 +34,11 @@ int main() {
 
    // roll die 60,000,000 times; use die value as frequency index
    for (int roll{1}; roll <= 60'000'000; ++roll) {
-       randomReal(engine);
+	   frequency[roll]++;
+//       randomReal(engine);
    }
 
+
    std::cout <<  "Face " <<  " Frequency  \n";
 
    // output each array element's value

CPlusPlus20ForProgrammers-master/examples/ch06/histogram.cpp

@@ -0,0 +1,60 @@
+// 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>
+
+template <int N>
+void accumulate(std::array<double, N>& histogram, double val, double lower, double upper){
+
+	double del {(upper-lower)/N};
+	for (int i{0}; i < N; i++){
+		if ( val > i*del && val < (i+1) * del )
+			histogram[i]++;
+	}
+	return;
+}
+
+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 
+
+   double upper_bound = 1;
+   double lower_bound = 0;
+   std::uniform_real_distribution<double> randomReal{lower_bound, upper_bound};
+
+   constexpr size_t N{10};
+   double del {(upper_bound-lower_bound)/N};
+   std::array<double, N> histogram{};
+
+   // roll die 60,000 times; use die value as frequency index
+   for (int roll{1}; roll <= 60'000; ++roll) {
+	   double val{ randomReal(engine)};
+	   accumulate<N>(histogram, val, lower_bound, upper_bound);
+   }
+
+
+   std::cout <<  " Histogram : \n";
+
+   // output each array element's value
+   for (size_t face{1}; face < histogram.size(); ++face) {
+      std::cout <<"Number of samples between " << lower_bound+face*del << " and " << lower_bound+(face+1)*del << " is " << 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.                     *
+ **************************************************************************/