array是一个固定大小的顺序容器，不能动态改变大小，array内的元素在内存中以严格的线性顺序存储

与普通数组声明存储空间大小[]的方式是一样有效的，只是加入了一些成员函数和全局函数[get (array)、operators (array)]，以便当作标准容器使用

零大小的array是有效的，但是不可以被成员函数front、back、data间接引用

array的swap是一个线性操作交换所有的元素，通常是非常低效的

Constructor:1.template < class T, size_t N > class array; 举例： array
      
        iArray={1,2,3,4,5,6,7,8,9,10};  
      

 

Member functions:

Iterators

 

begin	Return iterator to beginning
end	Return iterator to end
rbegin	Return reverse iterator to reverse beginning
rend	Return reverse iterator to reverse end
cbegin	Return const_iterator to beginning
cend	Return const_iterator to end
crbegin	Return const_reverse_iterator to reverse beginning
crend	Return const_reverse_iterator to reverse end

 

std::array
      
        arr = { 2, 16, 77, 34, 50 };  std::cout << "arr contains:";  for ( auto it = arr.cbegin(); it != arr.cend(); ++it ) {
     　　*it = 34;　　　　//error can't modify *it 　　arr.begin();　　//point to array first element 　　arr.front();　　//return the first element 　　arr.back();　　 //return the end element
      

　　std::cout << *it << std::endl; }

Capacity

 

empty	Test whether list is empty
size	Return size
max_size	Return maximum size

 

Element access

 

operator[]	Access element
at	Access element
front	Access first element
back	Access last element
data	Get pointer to first data

 注意：使用at程序崩溃时不会显示堆栈信息，尽量使用[]去array的值

 

back

std::array
         
           myarray = {
       5, 19, 77};  std::cout << "front is: " << myarray.front() << std::endl;   // 5  std::cout << "back is: " << myarray.back() << std::endl;     // 77  myarray.back() = 50;  for ( int& x : myarray ) 　　std::cout << " " << x;   //5 19 50
         

 

data//返回指向array中第一个元素的指针

const char* cstr = "Test string";  std::array
       
         charray;  std::memcpy (charray.data(),cstr,12);  std::cout << charray.data() << std::endl;//如果是char类型则打印值 Test string  //如果array中保存的是int  cout << iArray.data() << endl;//两者等效，等于打印出第一个元素的地址  cout << &charray << endl;  array
        
          sArray={
     "hello","c++","I"};  for (auto it = sArray.cbegin(); it != sArray.cend(); ++it)  {     cout << *it << '\t';//打印出hello  c++ I  }  cout << sArray.data() << endl;//打印地址
        
       

 

Modifiers

 

fill	Fill array with value
swap	Swap content

 

fill

std::array
       
         arr;arr.fill(34);for (auto it = arr.begin(); it != arr.end(); it++){    std::cout << " " << *it;}arr.assign(5);for (auto it = arr.begin(); it != arr.end(); it++){   std::cout << " " << *it;}
       

OutPut:  

 34 34 34 34 34 5 5 5 5 5

swap

std::array
         
           first = {
       10, 20, 30, 40, 50};  std::array
          
            second = {
       11, 22, 33, 44, 55};  first.swap (second);  std::cout << "first:";  for (int& x : first)     std::cout << " " << x;
          
         

Global functions

 

get(array)	Get element (tuple interface) (function template )
operators (array)	Global relational operator functions for array

 

get(array)//Returns a reference to the Ith element of array arr.

函数原型：1.template 
      
        T& get ( array
       
        & arr ) noexcept;2.template 
        
          T&& get ( array
         
          && arr ) noexcept;3.template 
          
            const T& get ( const array
           
            & arr ) noexcept;
           
          
         
        
       
      

 

std::array
         
           myarray = {
       10, 20, 30};  std::tuple
          
            mytuple (10, 20, 30);  std::tuple_element<0,decltype(myarray)>::type myelement;  // int [decltype是新标准中用来取类型]  //array头文件中重载了tuple_element和tuple_size方便和tuple交互  //交换myarray[0]和myarray[2]  myelement = std::get<2>(myarray);//取出array中的30  std::get<2>(myarray) = std::get<0>(myarray);//把array中的10换成30  std::get<0>(myarray) = myelement;//把30赋值给第一个元素  std::cout << "first element in myarray: " << std::get<0>(myarray) << "\n";  std::cout << "first element in mytuple: " << std::get<0>(mytuple) << "\n";
          
         

Output:

first element in myarray: 30

first element in mytuple: 10

operators(array)

模板原型如下：1.template 
      
           bool operator== ( const array
       
        & lhs, const array
        
         & rhs );2.template 
         
              bool operator!= ( const array
          
           & lhs, const array
           
            & rhs );3.template 
            
              bool operator< ( const array
             
              & lhs, const array
              
               & rhs );4template 
               
                 bool operator> ( const array
                
                 & lhs, const array
                 
                  & rhs );5.template 
                  
                    bool operator<= ( const array
                   
                    & lhs, const array
                    
                     & rhs );6.template 
                     
                       bool operator>= ( const array
                      
                       & lhs, const array
                       
                        & rhs );
                       
                      
                     
                    
                   
                  
                 
                
               
              
             
            
           
          
         
        
       
      

 

std::array
       
         a = {
     10, 20, 30, 40, 50};    std::array
        
          b = {
     10, 20, 30, 40, 50};    std::array
         
           c = {
     50, 40, 30, 20, 10};    if (a==b) std::cout << "a and b are equal\n";    if (b!=c) std::cout << "b and c are not equal\n";    if (b
          
           b) std::cout << "c is greater than b\n";    if (a<=b) std::cout << "a is less than or equal to b\n";    if (a>=b) std::cout << "a is greater than or equal to b\n";
          
         
        
       

Output:

a and b are equal

b and c are not equal

b is less than c

c is greater than b

a is less than or equal to b

a is greater than or equal to b