ch06 and ch07 sample codes were modified

CPlusPlus20ForProgrammers-master/examples/ch06/fig06_12.cpp

@@ -15,18 +15,63 @@ int multiply_int(int x, int y) {
 }
 
 
+double f(double& x){
+	return x*x;
+}
+
+template <typename T, typename F, long unsigned int N>
+T integrate (std::array<T, N> x, F f){
+	T tmp{T(0)};
+	for (auto s: x){
+            tmp+= f(s);
+	}
+	return tmp;
+}
+
+
+typedef double (*FUNC)(double&);
+
+
+template <typename T, long unsigned int N>
+T integrate2 (std::array<T, N> x, FUNC f){
+        T tmp{T(0)};
+        for (auto s: x){
+            tmp+= f(s);
+         }
+         return tmp;
+}
+
+
 int main() {
    constexpr std::array integers{1, 2, 3, 4, 5};
-   constexpr std::array floats {1.0, 2.0, 3.0, 4.0, 5.0};
+   std::array floats {1.0, 2.0, 3.0, 4.0, 5.0};
    auto multiply_lambda = [](const auto& x, const auto& y) {return x * y; };
 
+   auto f_lambda = [](auto& x) {return x*x;};
+
+   auto g_lambda = [&integers](auto& x) {
+	   auto tmp{0};
+	   for (int i{0};auto s: x){
+               tmp += s*integers[i];
+	   }
+	   return tmp;
+   };
+
    std::cout << "Product of integers: " <<  std::accumulate( std::begin(integers), std::end(integers), 1, multiply<int>) << "\n";
 
+   std::cout << "Product of integers: " <<  std::accumulate( integers.cbegin(), integers.cend(), 1, multiply<int>) << "\n";
+
    std::cout << "Product of integers with a lambda: " << std::accumulate(std::begin(integers), std::end(integers), 1, multiply_lambda) << "\n";
 
    std::cout << "Product of integers with a lambda: " << std::accumulate(std::begin(floats), std::end(floats), 1, multiply_int) << "\n";
 
    std::cout << "Product of integers with a lambda: " << std::accumulate(std::begin(floats), std::end(floats), 1, multiply_lambda) << "\n";
+
+   std::cout << "Integration2  template  " << integrate2(floats, f) << "\n";
+
+   std::cout << "Integration  full  template  " << integrate(floats, f_lambda) << "\n";
+
+   std::cout << "Lambda test   " << g_lambda(floats) << "\n";
 }
 
 

CPlusPlus20ForProgrammers-master/examples/ch06/fig06_13.cpp

@@ -1,7 +1,6 @@
 // fig06_13.cpp
 // Functional-style programming with C++20 ranges and views.
 #include <array>
-#include <fmt/format.h>
 #include <iostream>
 #include <numeric>
 #include <ranges>
@@ -10,10 +9,10 @@ int main() {
    // lambda to display results of range operations
    auto showValues{
       [](auto& values, const std::string& message) {
-         std::cout << fmt::format("{}: ", message);
+         std::cout <<  message << "\n";
 
          for (const auto& value : values) {
-            std::cout << fmt::format("{} ", value);
+            std::cout << value << " ";
          }
 
          std::cout << '\n';
@@ -40,8 +39,8 @@ int main() {
    showValues(values4, "Squares of even integers");
 
    // total the squares of the even integers 
-   std::cout << fmt::format("Sum squares of even integers 2-10: {}\n",
-      std::accumulate(std::begin(values4), std::end(values4), 0));
+   std::cout << "Sum squares of even integers 2-10: \n",
+      std::accumulate(std::begin(values4), std::end(values4), 0);
 
    // process a container's elements
    constexpr std::array numbers{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

CPlusPlus20ForProgrammers-master/examples/ch06/vector.cpp

@@ -0,0 +1,33 @@
+// resizing vector
+#include <iostream>
+#include <vector>
+#include <array>
+
+int main ()
+{
+  std::vector<int> myvector;
+  // set some initial content:
+  for (int i=1;i<10;i++) myvector.push_back(i);
+
+  myvector.resize(5);
+  std::cout << "myvector contains:";
+  for (int i=0;i<myvector.size();i++)
+    std::cout << ' ' << myvector[i];
+  std::cout << '\n';
+
+  myvector.resize(8,100);
+
+  std::cout << "myvector contains:";
+  for (int i=0;i<myvector.size();i++)
+    std::cout << ' ' << myvector[i];
+  std::cout << '\n';
+
+  myvector.resize(12);
+
+  std::cout << "myvector contains:";
+  for (int i=0;i<myvector.size();i++)
+    std::cout << ' ' << myvector[i];
+  std::cout << '\n';
+
+  return 0;
+}

CPlusPlus20ForProgrammers-master/examples/ch07/fig07_01.cpp

@@ -1,6 +1,7 @@
 // fig07_01.cpp
 // Pointer operators & and *.
 #include <iostream>
+#include <array>
 using namespace std;
 
 int main() {

CPlusPlus20ForProgrammers-master/examples/ch07/fig07_02.cpp

@@ -1,6 +1,5 @@
 // fig07_02.cpp
 // Pass-by-value used to cube a variable's value.
-#include <fmt/format.h>
 #include <iostream>
 
 int cubeByValue(int n); // prototype 
@@ -8,9 +7,9 @@ int cubeByValue(int n); // prototype
 int main() {
    int number{5};
 
-   std::cout << fmt::format("Original value of number is {}\n", number);
+   std::cout << "Original value of number is " << number << "\n";
    number = cubeByValue(number); // pass number by value to cubeByValue
-   std::cout << fmt::format("New value of number is {}\n", number);
+   std::cout << "New value of number is " << number <<"\n";
 }
 
 // calculate and return cube of integer argument                

CPlusPlus20ForProgrammers-master/examples/ch07/fig07_03.cpp

@@ -8,10 +8,10 @@ void cubeByReference(int* nPtr); // prototype
 
 int main() {
    int number{5};
+   std::cout << "Original value of number is " << number << "\n";
+   cubeByValue(number); // pass number by value to cubeByValue
+   std::cout << "New value of number is " << number <<"\n";
 
-   std::cout << fmt::format("Original value of number is {}\n", number);
-   cubeByReference(&number); // pass number address to cubeByReference
-   std::cout << fmt::format("New value of number is {}\n", number);
 }
 
 // calculate cube of *nPtr; modifies variable number in main 

CPlusPlus20ForProgrammers-master/examples/ch07/fig07_10.cpp

@@ -1,7 +1,6 @@
 // fig07_10.cpp
 // Sizeof operator when used on a built-in array's name
 // returns the number of bytes in the built-in array.
-#include <fmt/format.h>
 #include <iostream>
 
 size_t getSize(double* ptr); // prototype
@@ -9,11 +8,13 @@ size_t getSize(double* ptr); // prototype
 int main() {
    double numbers[20]; // 20 doubles; occupies 160 bytes on our system
 
-   std::cout << fmt::format("Number of bytes in numbers is {}\n\n",
-      sizeof(numbers));
 
-   std::cout << fmt::format("Number of bytes returned by getSize is {}\n",
-      getSize(numbers));
+
+   std::cout << "Number of bytes in numbers is " << sizeof(numbers)<<"\n";
+
+   std::cout << "Actual nukber of elements : " << sizeof(numbers)/sizeof(double) << "\n";
+
+   std::cout << "Number of bytes returned by getSize is " <<     getSize(numbers) << "\n";
 }
 
 // return size of ptr         

CPlusPlus20ForProgrammers-master/examples/ch07/fig07_13.cpp

@@ -1,13 +1,12 @@
 // fig07_13.cpp
 // Reading in command-line arguments.
-#include <fmt/format.h>
 #include <iostream>
 
 int main(int argc, char* argv[]) {
-   std::cout << fmt::format("Number of arguments: {}\n\n", argc);
+   std::cout << "Number of arguments: " << argc << "\n";
 
-   for (int i{0}; i < argc; ++i) {
-      std::cout << fmt::format("{}\n", argv[i]);
+   for (int i{1}; i < argc; ++i) {
+      std::cout << argv[i] <<  "\n" ;
    }
 }