Skip to main content

Initializer list in C++

C++ 11 Initializer :

 // C++ 03
class Dog {     // Aggregate class or struct
   public:
      int age;
      string name;
};

 Dog d1 = {5, "Henry"};   // Aggregate Initialization



// C++ 11 Initializer extended the scope of curly brace initialization.

 class Dog
 {
   public:
      Dog(int age, string name) {...};
};

 Dog d1 = {5, "Henry"}; 


/* Uniform Initialization Search Order:
 * 1. Initializer_list constructor
 * 2. Regular constructor that takes the appropriate parameters.
 * 3. Aggregate initializer.
 */

 Dog d1{3};

 class Dog 
{
   public:
   int age;                                // 3rd choice

    Dog(int a) 
   {                            // 2nd choice
      age = a;
   }

    Dog(const initializer_list& vec)  { // 1st choice
      age = *(vec.begin());      
   }
};
Labels:

Comments

Post a Comment

Popular posts from this blog

const used with functions

const used with functions : class Dog {    int age;    string name; public:    Dog() { age = 3; name = "dummy"; }         // const parameters and these are overloaded functions    void setAge(const int& a) { age = a; }    void setAge(int& a) { age = a; }         // Const return value    const string& getName() {return name;}         // const function and these are overloaded functions    void printDogName() const { cout << name << "const" << endl; }  // value of name can't be modified    void printDogName() { cout << getName() << " non-const" << endl; } }; int main() {    Dog d;    d.printDogName();        const Dog d2;    d2.printDogName();     }
Post a Comment
Read more

Structured Bindings

Returning multiple Values from function C++ 11 vs C++ 17 Returning compound objects Iterating over a compound collection Direct initialization Returning multiple Values from function C++ 11 vs C++ 17 :  C++ 11 (std::tie): std::tuple mytuple() {     char a = 'a';     int i = 123;     bool b = true;     return std::make_tuple(a, i, b);  // packing variable into tuple } To access return value using C++ 11, we would need something like: char a; int i; bool b; std::tie(a, i, b) = mytuple();  // unpacking tuple into variables Where the variables have to be defined before use and the types known in advance. C++ 17 : auto [a, i, b] = mytuple(); Returning compound objects :  This is the easy way to assign the individual parts of a compound type (such as a struct, pair etc) to different variables all in one go – and have the correct types automatically assigned. So let’s have a look at an ...
Post a Comment
Read more

POST 1 : std::thread in c++ | C++ 11

std::thread   C++  Thread support library std::thread. Threads enable programs to execute across several processor cores. Defined in header Class : thread Member types : native_handle_type Data Member  id    //represents the id of a thread (public member class) Member functions (constructor)    //constructs new thread object (public member function) (destructor)    //destructs the thread object, underlying thread must be joined or detached  (public member function) operator=    //moves the thread object  Observers  // Covered in NEXT POST Operations    // Covered in NEXT POST Constructor :   #include   void f1 ( int n ) { for ( int i = 0 ; i < 5 ; ++ i ) { std:: cout << "Thread 1 executing \n " ; ++ n ; std:: this_thread :: sleep_for ( std:: chrono :: milliseconds ( 10 ) ) ; ...
Post a Comment
Read more