Merge pull request #1 from adambard/master

update

1 files changed, 574 insertions, 34 deletions

diff --git a/c++.html.markdown b/c++.html.markdown
index 5f80f26f..8d1c7a26 100644
--- a/c++.html.markdown
+++ b/c++.html.markdown
@@ -4,7 +4,10 @@ filename: learncpp.cpp
 contributors:
     - ["Steven Basart", "http://github.com/xksteven"]
     - ["Matt Kline", "https://github.com/mrkline"]
-lang: en
+    - ["Geoff Liu", "http://geoffliu.me"]
+    - ["Connor Waters", "http://github.com/connorwaters"]
+    - ["Ankush Goyal", "http://github.com/ankushg07"]
+    - ["Jatin Dhankhar", "https://github.com/jatindhankhar"]
 ---
 
 C++ is a systems programming language that,
@@ -30,10 +33,9 @@ one of the most widely-used programming languages.
 
 // C++ is _almost_ a superset of C and shares its basic syntax for
 // variable declarations, primitive types, and functions.
-// However, C++ varies in some of the following ways:
 
-// A main() function in C++ should return an int,
-// though void main() is accepted by most compilers (gcc, clang, etc.)
+// Just like in C, your program's entry point is a function called
+// main with an integer return type.
 // This value serves as the program's exit status.
 // See http://en.wikipedia.org/wiki/Exit_status for more information.
 int main(int argc, char** argv)
@@ -51,11 +53,13 @@ int main(int argc, char** argv)
     return 0;
 }
 
-// In C++, character literals are one byte.
-sizeof('c') == 1
+// However, C++ varies in some of the following ways:
+
+// In C++, character literals are chars
+sizeof('c') == sizeof(char) == 1
 
-// In C, character literals are the same size as ints.
-sizeof('c') == sizeof(10)
+// In C, character literals are ints
+sizeof('c') == sizeof(int)
 
 
 // C++ has strict prototyping
@@ -146,7 +150,7 @@ namespace First {
 namespace Second {
     void foo()
     {
-        printf("This is Second::foo\n")
+        printf("This is Second::foo\n");
     }
 }
 
@@ -157,11 +161,12 @@ void foo()
 
 int main()
 {
-    // Assume everything is from the namespace "Second"
-    // unless otherwise specified.
+    // Includes all symbols from namespace Second into the current scope. Note
+    // that simply foo() no longer works, since it is now ambiguous whether
+    // we're calling the foo in namespace Second or the top level.
     using namespace Second;
 
-    foo(); // prints "This is Second::foo"
+    Second::foo(); // prints "This is Second::foo"
     First::Nested::foo(); // prints "This is First::Nested::foo"
     ::foo(); // prints "This is global foo"
 }
@@ -211,7 +216,7 @@ cout << myString + myOtherString; // "Hello World"
 
 cout << myString + " You"; // "Hello You"
 
-// C++ strings are mutable and have value semantics.
+// C++ strings are mutable.
 myString.append(" Dog");
 cout << myString; // "Hello Dog"
 
@@ -241,12 +246,135 @@ cout << fooRef; // Prints "I am foo. Hi!"
 // Doesn't reassign "fooRef". This is the same as "foo = bar", and
 //   foo == "I am bar"
 // after this line.
+cout << &fooRef << endl; //Prints the address of foo
 fooRef = bar;
+cout << &fooRef << endl; //Still prints the address of foo
+cout << fooRef;  // Prints "I am bar"
+
+//The address of fooRef remains the same, i.e. it is still referring to foo.
+
 
 const string& barRef = bar; // Create a const reference to bar.
 // Like C, const values (and pointers and references) cannot be modified.
 barRef += ". Hi!"; // Error, const references cannot be modified.
 
+// Sidetrack: Before we talk more about references, we must introduce a concept
+// called a temporary object. Suppose we have the following code:
+string tempObjectFun() { ... }
+string retVal = tempObjectFun();
+
+// What happens in the second line is actually:
+//   - a string object is returned from tempObjectFun
+//   - a new string is constructed with the returned object as argument to the
+//     constructor
+//   - the returned object is destroyed
+// The returned object is called a temporary object. Temporary objects are
+// created whenever a function returns an object, and they are destroyed at the
+// end of the evaluation of the enclosing expression (Well, this is what the
+// standard says, but compilers are allowed to change this behavior. Look up
+// "return value optimization" if you're into this kind of details). So in this
+// code:
+foo(bar(tempObjectFun()))
+
+// assuming foo and bar exist, the object returned from tempObjectFun is
+// passed to bar, and it is destroyed before foo is called.
+
+// Now back to references. The exception to the "at the end of the enclosing
+// expression" rule is if a temporary object is bound to a const reference, in
+// which case its life gets extended to the current scope:
+
+void constReferenceTempObjectFun() {
+  // constRef gets the temporary object, and it is valid until the end of this
+  // function.
+  const string& constRef = tempObjectFun();
+  ...
+}
+
+// Another kind of reference introduced in C++11 is specifically for temporary
+// objects. You cannot have a variable of its type, but it takes precedence in
+// overload resolution:
+
+void someFun(string& s) { ... }  // Regular reference
+void someFun(string&& s) { ... }  // Reference to temporary object
+
+string foo;
+someFun(foo);  // Calls the version with regular reference
+someFun(tempObjectFun());  // Calls the version with temporary reference
+
+// For example, you will see these two versions of constructors for
+// std::basic_string:
+basic_string(const basic_string& other);
+basic_string(basic_string&& other);
+
+// Idea being if we are constructing a new string from a temporary object (which
+// is going to be destroyed soon anyway), we can have a more efficient
+// constructor that "salvages" parts of that temporary string. You will see this
+// concept referred to as "move semantics".
+
+/////////////////////
+// Enums
+/////////////////////
+
+// Enums are a way to assign a value to a constant most commonly used for
+// easier visualization and reading of code
+enum ECarTypes
+{
+  Sedan,
+  Hatchback,
+  SUV,
+  Wagon
+};
+
+ECarTypes GetPreferredCarType()
+{
+	return ECarTypes::Hatchback;
+}
+
+// As of C++11 there is an easy way to assign a type to the enum which can be
+// useful in serialization of data and converting enums back-and-forth between
+// the desired type and their respective constants
+enum ECarTypes : uint8_t
+{
+  Sedan, // 0
+  Hatchback, // 1
+  SUV = 254, // 254
+  Hybrid // 255
+};
+
+void WriteByteToFile(uint8_t InputValue)
+{
+	// Serialize the InputValue to a file
+}
+
+void WritePreferredCarTypeToFile(ECarTypes InputCarType)
+{
+	// The enum is implicitly converted to a uint8_t due to its declared enum type
+	WriteByteToFile(InputCarType);
+}
+
+// On the other hand you may not want enums to be accidentally cast to an integer
+// type or to other enums so it is instead possible to create an enum class which
+// won't be implicitly converted
+enum class ECarTypes : uint8_t
+{
+  Sedan, // 0
+  Hatchback, // 1
+  SUV = 254, // 254
+  Hybrid // 255
+};
+
+void WriteByteToFile(uint8_t InputValue)
+{
+	// Serialize the InputValue to a file
+}
+
+void WritePreferredCarTypeToFile(ECarTypes InputCarType)
+{
+	// Won't compile even though ECarTypes is a uint8_t due to the enum
+	// being declared as an "enum class"!
+	WriteByteToFile(InputCarType);
+}
+
 //////////////////////////////////////////
 // Classes and object-oriented programming
 //////////////////////////////////////////
@@ -287,19 +415,22 @@ public:
 
     // Functions can also be defined inside the class body.
     // Functions defined as such are automatically inlined.
-    void bark() const { std::cout << name << " barks!\n" }
+    void bark() const { std::cout << name << " barks!\n"; }
 
     // Along with constructors, C++ provides destructors.
     // These are called when an object is deleted or falls out of scope.
     // This enables powerful paradigms such as RAII
     // (see below)
-    // Destructors must be virtual to allow classes to be derived from this one.
+    // The destructor should be virtual if a class is to be derived from;
+    // if it is not virtual, then the derived class' destructor will
+    // not be called if the object is destroyed through a base-class reference
+    // or pointer.
     virtual ~Dog();
 
 }; // A semicolon must follow the class definition.
 
 // Class member functions are usually implemented in .cpp files.
-void Dog::Dog()
+Dog::Dog()
 {
     std::cout << "A dog has been constructed\n";
 }
@@ -322,25 +453,28 @@ void Dog::print() const
     std::cout << "Dog is " << name << " and weighs " << weight << "kg\n";
 }
 
-void Dog::~Dog()
+Dog::~Dog()
 {
-    cout << "Goodbye " << name << "\n";
+    std::cout << "Goodbye " << name << "\n";
 }
 
 int main() {
     Dog myDog; // prints "A dog has been constructed"
     myDog.setName("Barkley");
     myDog.setWeight(10);
-    myDog.printDog(); // prints "Dog is Barkley and weighs 10 kg"
+    myDog.print(); // prints "Dog is Barkley and weighs 10 kg"
     return 0;
 } // prints "Goodbye Barkley"
 
 // Inheritance:
 
 // This class inherits everything public and protected from the Dog class
+// as well as private but may not directly access private members/methods
+// without a public or protected method for doing so
 class OwnedDog : public Dog {
 
-    void setOwner(const std::string& dogsOwner)
+public:
+    void setOwner(const std::string& dogsOwner);
 
     // Override the behavior of the print function for all OwnedDogs. See
     // http://en.wikipedia.org/wiki/Polymorphism_(computer_science)#Subtyping
@@ -424,7 +558,7 @@ int main () {
     Point up (0,1);
     Point right (1,0);
     // This calls the Point + operator
-    // Point up calls the + (function) with right as its paramater
+    // Point up calls the + (function) with right as its parameter
     Point result = up + right;
     // Prints "Result is upright (1,1)"
     cout << "Result is upright (" << result.x << ',' << result.y << ")\n";
@@ -432,6 +566,86 @@ int main () {
 }
 
 /////////////////////
+// Templates
+/////////////////////
+
+// Templates in C++ are mostly used for generic programming, though they are
+// much more powerful than generic constructs in other languages. They also
+// support explicit and partial specialization and functional-style type
+// classes; in fact, they are a Turing-complete functional language embedded
+// in C++!
+
+// We start with the kind of generic programming you might be familiar with. To
+// define a class or function that takes a type parameter:
+template<class T>
+class Box {
+public:
+    // In this class, T can be used as any other type.
+    void insert(const T&) { ... }
+};
+
+// During compilation, the compiler actually generates copies of each template
+// with parameters substituted, so the full definition of the class must be
+// present at each invocation. This is why you will see template classes defined
+// entirely in header files.
+
+// To instantiate a template class on the stack:
+Box<int> intBox;
+
+// and you can use it as you would expect:
+intBox.insert(123);
+
+// You can, of course, nest templates:
+Box<Box<int> > boxOfBox;
+boxOfBox.insert(intBox);
+
+// Until C++11, you had to place a space between the two '>'s, otherwise '>>'
+// would be parsed as the right shift operator.
+
+// You will sometimes see
+//   template<typename T>
+// instead. The 'class' keyword and 'typename' keywords are _mostly_
+// interchangeable in this case. For the full explanation, see
+//   http://en.wikipedia.org/wiki/Typename
+// (yes, that keyword has its own Wikipedia page).
+
+// Similarly, a template function:
+template<class T>
+void barkThreeTimes(const T& input)
+{
+    input.bark();
+    input.bark();
+    input.bark();
+}
+
+// Notice that nothing is specified about the type parameters here. The compiler
+// will generate and then type-check every invocation of the template, so the
+// above function works with any type 'T' that has a const 'bark' method!
+
+Dog fluffy;
+fluffy.setName("Fluffy")
+barkThreeTimes(fluffy); // Prints "Fluffy barks" three times.
+
+// Template parameters don't have to be classes:
+template<int Y>
+void printMessage() {
+  cout << "Learn C++ in " << Y << " minutes!" << endl;
+}
+
+// And you can explicitly specialize templates for more efficient code. Of
+// course, most real-world uses of specialization are not as trivial as this.
+// Note that you still need to declare the function (or class) as a template
+// even if you explicitly specified all parameters.
+template<>
+void printMessage<10>() {
+  cout << "Learn C++ faster in only 10 minutes!" << endl;
+}
+
+printMessage<20>();  // Prints "Learn C++ in 20 minutes!"
+printMessage<10>();  // Prints "Learn C++ faster in only 10 minutes!"
+
+
+/////////////////////
 // Exception Handling
 /////////////////////
 
@@ -439,19 +653,23 @@ int main () {
 // (see http://en.cppreference.com/w/cpp/error/exception)
 // but any type can be thrown an as exception
 #include <exception>
+#include <stdexcept>
 
 // All exceptions thrown inside the _try_ block can be caught by subsequent
 // _catch_ handlers.
 try {
     // Do not allocate exceptions on the heap using _new_.
-    throw std::exception("A problem occurred");
+    throw std::runtime_error("A problem occurred");
 }
+
 // Catch exceptions by const reference if they are objects
 catch (const std::exception& ex)
 {
-  std::cout << ex.what();
+    std::cout << ex.what();
+}
+
 // Catches any exception not caught by previous _catch_ blocks
-} catch (...)
+catch (...)
 {
     std::cout << "Unknown exception caught";
     throw; // Re-throws the exception
@@ -461,8 +679,8 @@ catch (const std::exception& ex)
 // RAII
 ///////
 
-// RAII stands for Resource Allocation Is Initialization.
-// It is often considered the most powerful paradigm in C++,
+// RAII stands for "Resource Acquisition Is Initialization".
+// It is often considered the most powerful paradigm in C++
 // and is the simple concept that a constructor for an object
 // acquires that object's resources and the destructor releases them.
 
@@ -483,16 +701,16 @@ void doSomethingWithAFile(const char* filename)
 // Unfortunately, things are quickly complicated by error handling.
 // Suppose fopen can fail, and that doSomethingWithTheFile and
 // doSomethingElseWithIt return error codes if they fail.
-// (Exceptions are the preferred way of handling failure,
-//  but some programmers, especially those with a C background,
-//  disagree on the utility of exceptions).
+//  (Exceptions are the preferred way of handling failure,
+//   but some programmers, especially those with a C background,
+//   disagree on the utility of exceptions).
 // We now have to check each call for failure and close the file handle
 // if a problem occurred.
 bool doSomethingWithAFile(const char* filename)
 {
     FILE* fh = fopen(filename, "r"); // Open the file in read mode
     if (fh == nullptr) // The returned pointer is null on failure.
-        reuturn false; // Report that failure to the caller.
+        return false; // Report that failure to the caller.
 
     // Assume each function returns false if it failed
     if (!doSomethingWithTheFile(fh)) {
@@ -513,7 +731,7 @@ bool doSomethingWithAFile(const char* filename)
 {
     FILE* fh = fopen(filename, "r");
     if (fh == nullptr)
-        reuturn false;
+        return false;
 
     if (!doSomethingWithTheFile(fh))
         goto failure;
@@ -535,7 +753,7 @@ void doSomethingWithAFile(const char* filename)
 {
     FILE* fh = fopen(filename, "r"); // Open the file in read mode
     if (fh == nullptr)
-        throw std::exception("Could not open the file.");
+        throw std::runtime_error("Could not open the file.");
 
     try {
         doSomethingWithTheFile(fh);
@@ -553,7 +771,7 @@ void doSomethingWithAFile(const char* filename)
 // Compare this to the use of C++'s file stream class (fstream)
 // fstream uses its destructor to close the file.
 // Recall from above that destructors are automatically called
-// whenver an object falls out of scope.
+// whenever an object falls out of scope.
 void doSomethingWithAFile(const std::string& filename)
 {
     // ifstream is short for input file stream
@@ -584,8 +802,330 @@ void doSomethingWithAFile(const std::string& filename)
 //   vector (i.e. self-resizing array), hash maps, and so on
 //   all automatically destroy their contents when they fall out of scope.
 // - Mutexes using lock_guard and unique_lock
+
+// containers with object keys of non-primitive values (custom classes) require
+// compare function in the object itself or as a function pointer. Primitives
+// have default comparators, but you can override it.
+class Foo {
+public:
+    int j;
+    Foo(int a) : j(a) {}
+};
+struct compareFunction {
+    bool operator()(const Foo& a, const Foo& b) const {
+        return a.j < b.j;
+    }
+};
+//this isn't allowed (although it can vary depending on compiler)
+//std::map<Foo, int> fooMap;
+std::map<Foo, int, compareFunction> fooMap;
+fooMap[Foo(1)]  = 1;
+fooMap.find(Foo(1)); //true
+
+///////////////////////////////////////
+// Lambda Expressions (C++11 and above)
+///////////////////////////////////////
+
+// lambdas are a convenient way of defining an anonymous function
+// object right at the location where it is invoked or passed as
+// an argument to a function.
+
+// For example, consider sorting a vector of pairs using the second
+// value of the pair
+
+vector<pair<int, int> > tester;
+tester.push_back(make_pair(3, 6));
+tester.push_back(make_pair(1, 9));
+tester.push_back(make_pair(5, 0));
+
+// Pass a lambda expression as third argument to the sort function
+// sort is from the <algorithm> header
+
+sort(tester.begin(), tester.end(), [](const pair<int, int>& lhs, const pair<int, int>& rhs) {
+        return lhs.second < rhs.second;
+    });
+
+// Notice the syntax of the lambda expression,
+// [] in the lambda is used to "capture" variables
+// The "Capture List" defines what from the outside of the lambda should be available inside the function body and how.
+// It can be either:
+//     1. a value : [x]
+//     2. a reference : [&x]
+//     3. any variable currently in scope by reference [&]
+//     4. same as 3, but by value [=]
+// Example:
+
+vector<int> dog_ids;
+// number_of_dogs = 3;
+for(int i = 0; i < 3; i++) {
+	dog_ids.push_back(i);
+}
+
+int weight[3] = {30, 50, 10};
+
+// Say you want to sort dog_ids according to the dogs' weights
+// So dog_ids should in the end become: [2, 0, 1]
+
+// Here's where lambda expressions come in handy
+
+sort(dog_ids.begin(), dog_ids.end(), [&weight](const int &lhs, const int &rhs) {
+        return weight[lhs] < weight[rhs];
+    });
+// Note we captured "weight" by reference in the above example.
+// More on Lambdas in C++ : http://stackoverflow.com/questions/7627098/what-is-a-lambda-expression-in-c11
+
+///////////////////////////////
+// Range For (C++11 and above)
+///////////////////////////////
+
+// You can use a range for loop to iterate over a container
+int arr[] = {1, 10, 3};
+
+for(int elem: arr){
+	cout << elem << endl;
+}
+
+// You can use "auto" and not worry about the type of the elements of the container
+// For example:
+
+for(auto elem: arr) {
+	// Do something with each element of arr
+}
+
+/////////////////////
+// Fun stuff
+/////////////////////
+
+// Aspects of C++ that may be surprising to newcomers (and even some veterans).
+// This section is, unfortunately, wildly incomplete; C++ is one of the easiest
+// languages with which to shoot yourself in the foot.
+
+// You can override private methods!
+class Foo {
+  virtual void bar();
+};
+class FooSub : public Foo {
+  virtual void bar();  // Overrides Foo::bar!
+};
+
+
+// 0 == false == NULL (most of the time)!
+bool* pt = new bool;
+*pt = 0; // Sets the value points by 'pt' to false.
+pt = 0;  // Sets 'pt' to the null pointer. Both lines compile without warnings.
+
+// nullptr is supposed to fix some of that issue:
+int* pt2 = new int;
+*pt2 = nullptr; // Doesn't compile
+pt2 = nullptr;  // Sets pt2 to null.
+
+// There is an exception made for bools.
+// This is to allow you to test for null pointers with if(!ptr),
+// but as a consequence you can assign nullptr to a bool directly!
+*pt = nullptr;  // This still compiles, even though '*pt' is a bool!
+
+
+// '=' != '=' != '='!
+// Calls Foo::Foo(const Foo&) or some variant (see move semantics) copy
+// constructor.
+Foo f2;
+Foo f1 = f2;
+
+// Calls Foo::Foo(const Foo&) or variant, but only copies the 'Foo' part of
+// 'fooSub'. Any extra members of 'fooSub' are discarded. This sometimes
+// horrifying behavior is called "object slicing."
+FooSub fooSub;
+Foo f1 = fooSub;
+
+// Calls Foo::operator=(Foo&) or variant.
+Foo f1;
+f1 = f2;
+
+
+///////////////////////////////////////
+// Tuples (C++11 and above)
+///////////////////////////////////////
+
+#include<tuple>
+
+// Conceptually, Tuples are similar to  old data structures (C-like structs) but instead of having named data members,
+// its elements are accessed by their order in the tuple.
+
+// We start with constructing a tuple.
+// Packing values into tuple
+auto first = make_tuple(10, 'A');
+const int maxN = 1e9;
+const int maxL = 15;
+auto second = make_tuple(maxN, maxL);
+
+// Printing elements of 'first' tuple
+cout << get<0>(first) << " " << get<1>(first) << "\n"; //prints : 10 A
+
+// Printing elements of 'second' tuple
+cout << get<0>(second) << " " << get<1>(second) << "\n"; // prints: 1000000000 15
+
+// Unpacking tuple into variables
+
+int first_int;
+char first_char;
+tie(first_int, first_char) = first;
+cout << first_int << " " << first_char << "\n";  // prints : 10 A
+
+// We can also create tuple like this.
+
+tuple<int, char, double> third(11, 'A', 3.14141);
+// tuple_size returns number of elements in a tuple (as a constexpr)
+
+cout << tuple_size<decltype(third)>::value << "\n"; // prints: 3
+
+// tuple_cat concatenates the elements of all the tuples in the same order.
+
+auto concatenated_tuple = tuple_cat(first, second, third);
+// concatenated_tuple becomes = (10, 'A', 1e9, 15, 11, 'A', 3.14141)
+
+cout << get<0>(concatenated_tuple) << "\n"; // prints: 10
+cout << get<3>(concatenated_tuple) << "\n"; // prints: 15
+cout << get<5>(concatenated_tuple) << "\n"; // prints: 'A'
+
+
+/////////////////////
+// Containers
+/////////////////////
+
+// Containers or the Standard Template Library are some predefined templates.
+// They manage the storage space for its elements and provide
+// member functions to access and manipulate them.
+
+// Few containers are as follows:
+
+// Vector (Dynamic array)
+// Allow us to Define the Array or list of objects at run time
+#include <vector>
+string val;
+vector<string> my_vector; // initialize the vector
+cin >> val;
+my_vector.push_back(val); // will push the value of 'val' into vector ("array") my_vector
+my_vector.push_back(val); // will push the value into the vector again (now having two elements)
+
+// To iterate through a vector we have 2 choices:
+// Either classic looping (iterating through the vector from index 0 to its last index):
+for (int i = 0; i < my_vector.size(); i++) {
+	cout << my_vector[i] << endl; // for accessing a vector's element we can use the operator []
+}
+
+// or using an iterator:
+vector<string>::iterator it; // initialize the iterator for vector
+for (it = my_vector.begin(); it != my_vector.end(); ++it) {
+	cout << *it  << endl;
+}
+
+// Set
+// Sets are containers that store unique elements following a specific order.
+// Set is a very useful container to store unique values in sorted order
+// without any other functions or code.
+
+#include<set>
+set<int> ST;    // Will initialize the set of int data type
+ST.insert(30);  // Will insert the value 30 in set ST
+ST.insert(10);  // Will insert the value 10 in set ST
+ST.insert(20);  // Will insert the value 20 in set ST
+ST.insert(30);  // Will insert the value 30 in set ST
+// Now elements of sets are as follows
+//  10 20 30
+
+// To erase an element
+ST.erase(20);  // Will erase element with value 20
+// Set ST: 10 30
+// To iterate through Set we use iterators
+set<int>::iterator it;
+for(it=ST.begin();it<ST.end();it++) {
+	cout << *it << endl;
+}
+// Output:
+// 10
+// 30
+
+// To clear the complete container we use Container_name.clear()
+ST.clear();
+cout << ST.size();  // will print the size of set ST
+// Output: 0
+
+// NOTE: for duplicate elements we can use multiset
+
+// Map
+// Maps store elements formed by a combination of a key value
+// and a mapped value, following a specific order.
+
+#include<map>
+map<char, int> mymap;  // Will initialize the map with key as char and value as int
+
+mymap.insert(pair<char,int>('A',1));
+// Will insert value 1 for key A
+mymap.insert(pair<char,int>('Z',26));
+// Will insert value 26 for key Z
+
+// To iterate
+map<char,int>::iterator it;
+for (it=mymap.begin(); it!=mymap.end(); ++it)
+    std::cout << it->first << "->" << it->second << '\n';
+// Output:
+// A->1
+// Z->26
+
+// To find the value corresponding to a key
+it = mymap.find('Z');
+cout << it->second;
+
+// Output: 26
+
+
+///////////////////////////////////
+// Logical and Bitwise operators
+//////////////////////////////////
+
+// Most of the operators in C++ are same as in other languages
+
+// Logical operators
+
+// C++ uses Short-circuit evaluation for boolean expressions, i.e, the second argument is executed or
+// evaluated only if the first argument does not suffice to determine the value of the expression
+
+true && false // Performs **logical and** to yield false
+true || false // Performs **logical or** to yield true
+! true        // Performs **logical not** to yield false
+
+// Instead of using symbols equivalent keywords can be used
+true and false // Performs **logical and** to yield false
+true or false  // Performs **logical or** to yield true
+not true       // Performs **logical not** to yield false
+
+// Bitwise operators
+
+// **<<** Left Shift Operator
+// << shifts bits to the left
+4 << 1 // Shifts bits of 4 to left by 1 to give 8
+// x << n can be thought as x * 2^n
+
+
+// **>>** Right Shift Operator
+// >> shifts bits to the right
+4 >> 1 // Shifts bits of 4 to right by 1 to give 2
+// x >> n can be thought as x / 2^n
+
+~4    // Performs a bitwise not
+4 | 3 // Performs bitwise or
+4 & 3 // Performs bitwise and
+4 ^ 3 // Performs bitwise xor
+
+// Equivalent keywords are
+compl 4    // Performs a bitwise not
+4 bitor 3  // Performs bitwise or
+4 bitand 3 // Performs bitwise and
+4 xor 3    // Performs bitwise xor
+
+
 ```
-Futher Reading:
+Further Reading:
 
 An up-to-date language reference can be found at
 <http://cppreference.com/w/cpp>