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C++ is an open source programming language created in 1985 by Bjarne Stroustrup.

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C++ ( pronounced cee plus plus) is a general-purpose programming language. It has imperative, object-oriented and generic programming features, while also providing facilities for low-level memory manipulation. It was designed with a bias toward system programming and embedded, resource-constrained and large systems, with performance, efficiency and flexibility of use as its design highlights. Read more on Wikipedia...


Example from Compiler Explorer:
// Type your code here, or load an example. int square(int num) { return num * num; }
Example from Riju:
#include <iostream> int main() { std::cout << "Hello, world!" << std::endl; return 0; }
Example from hello-world:
#include <iostream> int main() { std::cout << "Hello World" << std::endl; }
Example from the Hello World Collection:
// Hello World in C++ (pre-ISO) #include <iostream.h> main() { cout << "Hello World!" << endl; return 0; }
Example from Linguist:
#include <cstdint> namespace Gui { }
Example from Wikipedia:
1 #include <iostream> 2 #include <vector> 3 #include <stdexcept> 4 5 int main() { 6 try { 7 std::vector<int> vec{3, 4, 3, 1}; 8 int i{vec.at(4)}; // Throws an exception, std::out_of_range (indexing for vec is from 0-3 not 1-4) 9 } 10 // An exception handler, catches std::out_of_range, which is thrown by vec.at(4) 11 catch (std::out_of_range &e) { 12 std::cerr << "Accessing a non-existent element: " << e.what() << '\n'; 13 } 14 // To catch any other standard library exceptions (they derive from std::exception) 15 catch (std::exception &e) { 16 std::cerr << "Exception thrown: " << e.what() << '\n'; 17 } 18 // Catch any unrecognised exceptions (i.e. those which don't derive from std::exception) 19 catch (...) { 20 std::cerr << "Some fatal error\n"; 21 } 22 }
C++ Keywords
#define #defined #elif #else #endif #error #if #ifdef #ifndef #include #line #pragma #undef alignas alignof and and_eq asm atomic_cancel atomic_commit atomic_noexcept auto bitand bitor bool break case catch char char16_t char32_t class compl concept const constexpr const_cast continue decltype default delete do double dynamic_cast else enum explicit export extern false final float for friend goto if inline int import long module mutable namespace new noexcept not not_eq nullptr operator or or_eq override private protected public register reinterpret_cast requires return short signed sizeof static static_assert static_cast struct switch synchronized template this thread_local throw transaction_safe transaction_safe_dynamic true try typedef typeid typename union unsigned using virtual void volatile wchar_t while xor xor_eq

Language features

Feature Supported Example Token
Standard Library ✓ #include
Access Modifiers ✓
Exceptions ✓
Classes ✓
Threads ✓
Virtual function ✓ 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; } };
Templates ✓ template Vector& Vector::operator+=(const Vector& rhs) { for (int i = 0; i < length; ++i) value[i] += rhs.value[i]; return *this; }
Explicit Standard Library ✓ #include
Operator Overloading ✓
Multiple Inheritance ✓
Namespaces ✓ #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 }
Function Overloading ✓ // 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); }
Iterators ✓ 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. }
Constructors ✓ 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);
Single Dispatch ✓
Partial Application ✓ // 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; }
Magic Getters and Setters X
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