Add the first two chapters of the Book

The first two chapters of the companion book are now reasonably
updated, and can be added to the course material.

Book/chapter1/examples/control_flow.cc

+#include <iostream>
+
+void say_hello()
+{
+    std::cout << "Hello!\n";
+}
+
+auto add(int input1, int input2) -> int
+{
+    return input1 + input2;
+}
+
+auto sub(int input1, int input2) -> int
+{
+    return input1 - input2;
+}
+
+auto main() -> int
+{
+    auto v1 = add(34552, 88112);
+    auto v2 = add(v1, sub(335, 88112));
+    say_hello();
+    std::cout << "v1 has value : " << v1 << "\n";
+    std::cout << "v2 has value : " << v2 << "\n";
+}
+

Book/chapter1/examples/hello.cc

+#include <iostream>
+
+auto main() -> int
+{
+    std::cout << "Hello, world!\n";
+}

Book/chapter1/examples/hello2.cc

+#include <print>
+#include <numeric>
+
+auto main() -> int
+{
+    auto x = 2147483645, y = 2147483641;
+
+    std::print("Mid-point of {} and {} is {}\n", x, y, std::midpoint(x, y));
+
+    std::print("Naive mid-point of {} and {} is {}\n", x, y, (x + y)/2);
+}
+

Book/chapter1/examples/hello2b.cc

+#include <iostream>
+#include <numeric>
+
+auto main() <- int
+{
+    auto x = 2147483645, y = 2147483641;
+    std::cout << "Mid-point of " << x << " and "<<  y << " is " << std::midpoint(x, y) << "\n";
+    std::cout << "Naive mid-point of " << x << " and " << y << " is " << (x + y)/2 << "\n";
+}
+

Book/chapter1/examples/hello3.cc

+#include <iostream>
+#include <numeric>
+
+auto main() <- int
+{
+    auto x = 1000000005, y = 2000403030;
+
+    std::cout << "The greatest common divisor of ";
+              << x << " and " << y << " is " 
+              << std::gcd(x, y) << "\n";
+
+}
+

Book/chapter1/examples/hello3b.cc

+// examples/hello3b.cc // broken code for you to fix!
+#include <print>
+#include <numeric>
+
+auto main() -> int
+{
+    auto x = 1000000005, y = 2000403030;
+
+    std::print("The greatest common divisor of {} and {} is {}\n",
+               x, y, std::gcd(x, y));
+}
+

Book/chapter1/examples/hello3c.cc

+// examples/hello3c.cc
+#include <print>
+#include <numeric>
+
+auto main() -> int
+{
+    auto x = 1000000005, y = 2000403030;
+
+    std::print("The greatest common divisor of {2} and {1} is {0}\n",
+               std::gcd(x, y), y, x);
+}
+

Book/chapter1/examples/hello3d.cc

+// examples/hello3d.cc
+#include <print>
+#include <numeric>
+
+auto main() -> int
+{
+    auto x = 1000000005, y = 2000403030;
+
+    std::print("The greatest common divisor of {2:0>12} and {1:0>12} is {0: <}\n",
+               std::gcd(x, y), y, x);
+    std::print("The greatest common divisor of {2:0>12} and {1:0>12} is {0: <}\n",
+               std::gcd(132, 90), 90, 132);
+    std::print("The greatest common divisor of {2:0>12} and {1:0>12} is {0: <}\n",
+               std::gcd(51768, 77924), 77924, 51768);
+}
+

Book/chapter1/examples/hello4.cc

+#include <iostream>
+#include 'numeric'
+
+pkw main()
+{
+    auto x = 15, y = 24;
+
+    std::cout << "The least common multiple of "
+              << x << " and " << y << " is " 
+              << std::lcm(x, y) << "\n";
+
+}
+

Book/chapter1/examples/hello_cxx23.cc

+#include <print>
+
+auto main() -> int
+{
+    std::println("Hello world!");
+}
+

Book/chapter1/examples/math_functions.cc

+// examples/math_functions.cc
+#include <cmath>
+#include <iostream>
+auto main() -> int
+{
+    double inp = 3.141592653 / 6.0;
+    //
+    std::cout << "Enter angle: ";
+    //
+    std::cin >> inp;
+    std::cout << "sqrt(" << inp << ") = " << std::sqrt(inp) << "\n";
+    std::cout << "cbrt(" << inp << ") = " << std::cbrt(inp) << "\n";
+    std::cout << "cos(" << inp << ") = " << std::cos(inp) << "\n";
+    std::cout << "sin(" << inp << ") = " << std::sin(inp) << "\n";
+    std::cout << "cosh(" << inp << ") = " << std::cosh(inp) << "\n";
+    std::cout << "sinh(" << inp << ") = " << std::sinh(inp) << "\n";
+    std::cout << "exp(" << inp << ") = " << std::exp(inp) << "\n";
+    std::cout << "erf(" << inp << ") = " << std::erf(inp) << "\n";
+    std::cout << "riemann_zeta(" << inp << ") = " << std::riemann_zeta(inp) << "\n";
+}

Book/chapter1/examples/math_functions_cmdln.cc

+// examples/math_functions_cmdln.cc
+#include <cmath>
+#include <iostream>
+#include <string>
+auto main(int argc, char* argv[]) -> int
+{
+    double inp = 3.141592653 / 6.0;
+    if (argc > 1)
+        inp = std::stod(argv[1]);
+    std::cout << "sqrt(" << inp << ") = " << std::sqrt(inp) << "\n";
+    std::cout << "cbrt(" << inp << ") = " << std::cbrt(inp) << "\n";
+    std::cout << "cos(" << inp << ") = " << std::cos(inp) << "\n";
+    std::cout << "sin(" << inp << ") = " << std::sin(inp) << "\n";
+    std::cout << "cosh(" << inp << ") = " << std::cosh(inp) << "\n";
+    std::cout << "sinh(" << inp << ") = " << std::sinh(inp) << "\n";
+    std::cout << "exp(" << inp << ") = " << std::exp(inp) << "\n";
+    std::cout << "erf(" << inp << ") = " << std::erf(inp) << "\n";
+    std::cout << "riemann_zeta(" << inp << ") = " << std::riemann_zeta(inp) << "\n";
+}

Book/chapter1/examples/outside.cc

+#include <iostream>
+#include <cmath>
+
+sin(3.0);
+
+int main()
+{
+    double x = 2.1;
+    x = x * x * x;
+    std::cout << x << "\n";
+}
+

Book/chapter1/examples/print0.cc

+#include <print>
+
+auto main() -> int
+{
+    std::print();
+}
+

Book/chapter2/examples/G_potential.cc

+#include <iostream>
+#include <vector>
+
+auto main() -> int
+{
+    const auto G = 6.674e-11;
+    std::vector x{ 0., 1., 2., 3., 4., 5. };
+    std::vector y{ 0., 1., 2., 3., 4., 5. };
+    std::vector z{ 0., 1., 2., 3., 4., 5. };
+    std::vector m{ 1.0e5, 1.0e5, 2.0e5, 1.0e5, 1.0e5, 1.0e5 };
+    int size = x.size();
+    
+    auto total = 0.;
+    // loop over index i from 0 till size.
+    // loop over index j from i+1 till size
+    // figure out where to put the end of the loops
+    auto dx = x[i] - x[j];
+    auto dy = y[i] - y[j];
+    auto dz = z[i] - z[j];
+    auto r2 = dx * dx + dy * dy + dz * dz;
+    total = total + G * m[i] * m[j] / r2;
+}
+    std::cout << "Total gravitational potential energy = " << total << "\n";
+
+}
+

Book/chapter2/examples/array_or_pointer.cc

+// examples/array_or_pointer.cc
+#include <iostream>
+
+auto f(double arr[4]) -> void
+{
+    std::cout << "size of function argument in bytes = " << sizeof(decltype(arr)) << "\n";
+    std::cout << *arr << "\n";
+}
+
+auto main() -> int
+{
+    double v[4]{1, 2, 3, 4};
+    std::cout << "Elements of raw array...\n";
+    for (auto a : v) std::cout << a << "\n";
+  
+    std::cout << "size of raw array in bytes = " << sizeof(decltype(v)) << "\n";
+    f(v);
+}
+

Book/chapter2/examples/asan0.cc

+// examples/asan0.cc
+auto main() -> int
+{
+    auto* X = new double[400]; // space for 400 doubles reserved on the heap
+    // X holds the address of where those 400 doubles are on the heap.
+    // For instance, X could be the numeric address 337932100.
+    // work with X, e.g.,
+    if (X != nullptr) {
+        for (int i = 0; i < 400; ++i) {
+            X[i] = 0;
+        }
+    }
+
+    // Done with calculations using X
+    delete[] X; // Previously allocated space for 400 doubles is now released
+    // X is still 337932100, but the previously allocated 400 doubles at
+    // that address on the heap is already gone!
+
+    if (X != nullptr) {
+        for (int i = 0; i < 400; ++i) {
+            X[i] = 1;
+        }
+        return X[33] > X[23];
+    }
+}

Book/chapter2/examples/binform.cc

+#include <bit>
+#include <bitset>
+#include <concepts>
+#include <cstddef>
+#include <iomanip>
+#include <iostream>
+
+template <class T>
+concept Number = std::floating_point<T> || std::integral<T>;
+
+using std::byte;
+
+template <Number T>
+auto bits(const T& var)
+{
+    auto loc { var };
+    unsigned long bytes { 0UL };
+    byte* in = reinterpret_cast<byte*>(&loc);
+    byte* out = reinterpret_cast<byte*>(&bytes);
+    std::copy(in, in + sizeof(T), out);
+    return std::bitset<8 * sizeof(T)>(bytes);
+}
+
+void showbits(double var)
+{
+    std::cout << "bits for double value " << var << "\n";
+    auto b = bits(var).to_string();
+    std::cout << "raw = " << b << "\n";
+    std::cout << "sign  exponent          mantissa\n"
+              << std::setw(6) << std::left << b[0]
+              << std::setw(16) << std::left << b.substr(1UL, 11)
+              << "  " << b.substr(12) << "\n\n";
+}
+
+void showbits(float var)
+{
+    std::cout << "bits for float value " << var << "\n";
+    auto b = bits(var).to_string();
+    std::cout << "raw = " << b << "\n";
+    std::cout << "sign  exponent          mantissa\n"
+              << std::setw(6) << std::left << b[0]
+              << std::setw(16) << std::left << b.substr(1UL, 8)
+              << "  " << b.substr(9) << "\n\n";
+}
+
+void showbits(auto var)
+{
+    std::cout << "bits for " << var << " with non-floating point type : " << bits(var) << "\n";
+}
+
+int main()
+{
+    showbits(1);
+    showbits(1U - 2U);
+    showbits(-1);
+    showbits(1.0);
+    showbits(1.25);
+    showbits(1.25F);
+    showbits(1.5);
+    showbits(1.75);
+    showbits(2.0);
+    showbits(2.25);
+    showbits(2.5);
+    showbits(2.75);
+    showbits(3.0);
+    showbits(4.0);
+    showbits(8.0);
+    showbits(0.0);
+    showbits(-0.0);
+    std::cout << "-0.0 == 0.0 is " << std::boolalpha << (-0.0 == 0.0) << "\n\n";
+    showbits(1.0e-100);
+    std::cout << "1.0e-100 == 0.0 is " << std::boolalpha << (1.0e-100 == 0.0) << "\n\n";
+    showbits(8UL);
+}

Book/chapter2/examples/binform17.cc

+#include <bitset>
+#include <cstddef>
+#include <iomanip>
+#include <iostream>
+
+using byte = unsigned char;
+
+template <class T>
+auto bits(T var)
+{
+    unsigned long bytes { 0UL };
+    byte* in = reinterpret_cast<byte*>(&var);
+    byte* out = reinterpret_cast<byte*>(&bytes);
+    std::copy(in, in + sizeof(var), out);
+    return std::bitset<8 * sizeof(decltype(var))>(bytes);
+}
+
+void showbits(double var)
+{
+    std::cout << "bits for double value " << var << "\n";
+    auto b = bits(var).to_string();
+    std::cout << "raw = " << b << "\n";
+    std::cout << "sign  exponent          mantissa\n"
+              << std::setw(6) << std::left << b[0]
+              << std::setw(16) << std::left << b.substr(1UL, 11)
+              << "  " << b.substr(12) << "\n\n";
+}
+
+void showbits(float var)
+{
+    std::cout << "bits for float value " << var << "\n";
+    auto b = bits(var).to_string();
+    std::cout << "raw = " << b << "\n";
+    std::cout << "sign  exponent          mantissa\n"
+              << std::setw(6) << std::left << b[0]
+              << std::setw(16) << std::left << b.substr(1UL, 8)
+              << "  " << b.substr(9) << "\n\n";
+}
+
+template <class T>
+void showbits(T var)
+{
+    std::cout << "bits for " << var << " with non-floating point type : " << bits(var) << "\n";
+}
+
+int main()
+{
+    showbits(1);
+    showbits(1U - 2U);
+    showbits(-1);
+    showbits(1.0);
+    showbits(1.25);
+    showbits(1.25F);
+    showbits(1.5);
+    showbits(1.75);
+    showbits(2.0);
+    showbits(4.0);
+    showbits(8.0);
+    showbits(0.0);
+    showbits(-0.0);
+    std::cout << "-0.0 == 0.0 is " << std::boolalpha << (-0.0 == 0.0) << "\n\n";
+    showbits(1.0e-100);
+    std::cout << "1.0e-100 == 0.0 is " << std::boolalpha << (1.0e-100 == 0.0) << "\n\n";
+    showbits(8UL);
+}