C++ 11 Feature

Chapter 2: Variable and Basic Types

• List Initialization
• nullptr
• constexpr
• Alias Declaration:
  • using SI = Sales_item;
• auto
• decltype

Chapter 3: Strings, Vectors, and Arrays

• for(declaration : expression):
  • expression -> vector, array[], string
• List Initialization:

  vector<string> articles = {"a", "an", "the"};
  

• The .cbegin() and .cend() Operations in Iterator:

  vector<int> v;
  auto it = v.cbegin(); // it has type vector<int>::const_iterator
  

• The Library begin() and end() Functions:

  int ia[] = {0,1,2,3,4,5,6,7,8,9}; // ia is an array of ten ints 
  int *beg = begin(ia); // pointer to the first element in ia
  int *last = end(ia); // pointer one past the last element in ia
  

  - Multidimensionfor loop application:

  size_t cnt = 0;
  for (auto &row : ia) // for every element in the outer array 
      for (auto &col : row) { // for every element in the inner array col = cnt; // give this element the next value
          ++cnt; // increment cnt 
      }
  

Pointer:

• Function pointer: std::bind(),std::function<>

  #include<function>
  
  using namespace std;
  using namespace placeholder;
  
  int add(int a, int b){
      return a + b;
  }
  
  auto func = bind(add, _1, 20);
  
  cout << func(10) << endl;
  // result: 30
  

• Smart pointer: unique_ptr

  #include<iostream>
  #include<memory>
  
  using namespace std;
  
  class Test {
  public:
      Test() {
          cout << "created" << endl;
      }
  
      ~Test() {
          cout << "destroy" << endl;
      }
  
      void greet() {
          cout << "Hello" << endl;
      }
  };
  
  class Temp {
  private:
      unique_ptr<Test[]> pTest_;
  public:
      Temp() : pTest_(new Test[2]) {}
  };
  
  int main()
  {
      Temp temp;
  
      cout << "finished" << endl;
  
      return 0;
  }
  // pTest_ will be delete when temp out of the scope.
  

• Smart pointer: shared_ptr

  int main()
  {
      shared_ptr<Test> test2(nullptr);
  
      {
          shared_ptr<Test> test1 = make_shared<Test>();
          test2 = test1;
      }
  
      cout << "finished" << endl;
  
      return 0;
  }
  // result: 
  // "created"
  // "finished"
  // "destroy"
  
  // shared_ptr will be delete until all of same address pointer out of scope.