/* A comment
*/

class Animal {
 public:
  // Intentionally not virtual:
  void Move(void) {
    std::cout << "This animal moves in some way" << std::endl;
  }
  virtual void Eat(void) = 0;
};

// The class "Animal" may possess a definition for Eat if desired.
class Llama : public Animal {
 public:
  // The non virtual function Move is inherited but not overridden.
  void Eat(void) override {
    std::cout << "Llamas eat grass!" << std::endl;
  }
};

// A comment

template 
Vector& Vector::operator+=(const Vector& rhs)
{
    for (int i = 0; i < length; ++i)
        value[i] += rhs.value[i];
    return *this;
}

cout<<"hello world." << std::endl;

#include 
using namespace std;

// Variable created inside namespace
namespace first
{
  int val = 500;
}
 
// Global variable
int val = 100;
// Ways to do it: https://en.cppreference.com/w/cpp/language/namespace
namespace ns_name { declarations }
inline namespace ns_name { declarations }
namespace { declarations }
ns_name::name
using namespace ns_name;
using ns_name::name;
namespace name = qualified-namespace ;
namespace ns_name::inline(since C++20)(optional) name { declarations } 

// volume of a cube
int volume(const int s) {
 return s*s*s;
}
// volume of a cylinder
double volume(const double r, const int h) {
  return 3.1415926*r*r*static_cast(h);
}

https://msdn.microsoft.com/en-us/library/503x3e3s.aspx

std::vector items;
items.push_back(5);  // Append integer value '5' to vector 'items'.
items.push_back(2);  // Append integer value '2' to vector 'items'.
items.push_back(9);  // Append integer value '9' to vector 'items'.

for (auto it = items.begin(); it != items.end(); ++it) {  // Iterate through 'items'.
  std::cout << *it;  // And print value of 'items' for current index.
}

// #pragma once is a non-standard but widely supported preprocessor directive designed to cause the current source file to be included only once in a single compilation.
#pragma once
struct foo
{
   int member;
};

// C/C++ program to check if a number is 
// even or not using goto statement 
#include  
using namespace std; 
  
// function to check even or not 
void checkEvenOrNot(int num) 
{ 
    if (num % 2 == 0) 
        goto even; // jump to even 
    else
        goto odd; // jump to odd 
  
even: 
    cout << num << " is evenn"; 
    return; // return if even 
odd: 
    cout << num << " is oddn"; 
} 
  
// Driver program to test above function 
int main() 
{ 
    int num = 26; 
    checkEvenOrNot(num); 
    return 0; 
}

"hello world"

int const one = 1;

class Foobar {
 public:
  Foobar(double r = 1.0,
         double alpha = 0.0)  // Constructor, parameters with default values.
      : x_(r * cos(alpha))    // <- Initializer list
  {
    y_ = r * sin(alpha);  // <- Normal assignment
  }

 private:
  double x_;
  double y_;
};
Foobar a,
       b(3),
       c(5, M_PI/4);

// http://www.cplusplus.com/reference/functional/bind/
// bind example
#include      // std::cout
#include    // std::bind

// a function: (also works with function object: std::divides my_divide;)
double my_divide (double x, double y) {return x/y;}

struct MyPair {
  double a,b;
  double multiply() {return a*b;}
};

int main () {
  using namespace std::placeholders;    // adds visibility of _1, _2, _3,...

  // binding functions:
  auto fn_five = std::bind (my_divide,10,2);               // returns 10/2
  std::cout << fn_five() << '\n';                          // 5

  auto fn_half = std::bind (my_divide,_1,2);               // returns x/2
  std::cout << fn_half(10) << '\n';                        // 5

  auto fn_invert = std::bind (my_divide,_2,_1);            // returns y/x
  std::cout << fn_invert(10,2) << '\n';                    // 0.2

  auto fn_rounding = std::bind (my_divide,_1,_2);     // returns int(x/y)
  std::cout << fn_rounding(10,3) << '\n';                  // 3

  MyPair ten_two {10,2};

  // binding members:
  auto bound_member_fn = std::bind (&MyPair::multiply,_1); // returns x.multiply()
  std::cout << bound_member_fn(ten_two) << '\n';           // 20

  auto bound_member_data = std::bind (&MyPair::a,ten_two); // returns ten_two.a
  std::cout << bound_member_data() << '\n';                // 10

  return 0;
}

int count = 2;
count++;
++count;
count--;
--count;
&count; // address
*count; // indirection
+count; // Positive
-count; // negative
~count; // one's complement
!x; // logical negation
sizeof count;
sizeof(int);
(float)count;

int i = 0;

int i = 0;

int *p;

#include