The principle and use of the c++11 array

An array is added to the c++11 in place of the original C language.
At the same time, the use of dynamic array new and delete is avoided, and the memory is automatically managed.
Moreover, the execution efficiency is higher than the vector.


A definition
defined in the array header file:

template<     class T,     std::size_t N > struct array;

If we were to write an array template class ourselves, we would probably want to look like this:

Template <typename T, int n>class myarray{public  :    MyArray () {a = new t[n];}    ~myarray () {delete[] A;}    t& operator[] (int i) {return * (a+i);}  Private:    t* A;};

21-D Arrays
1 statement

Array<int, 5> arr1 = {1, 2, 3, 4, 5};

Or

Array<int, 5> arr1{{1, 2, 3, 4, 5}};

2 Visits
For example: Take the first element of an array

3 traversal

for (size_t i = 0; i < arr1.size (); ++i) {cout << arr1[0]<< endl;//cout << arr1.at (0) << Endl;}

32-D Arrays
1 statement

Array<array<int, 3>, 2> arr2d = {11,12,13,21,22,23};

2 Visits
For example: Or take the first element

int n3 = arr2d[0][0];

3 traversal

for (size_t i = 0; i < arr2d.size (), ++i) {for (size_t j= 0; J < arr2d[i].size (); ++j) {cout << arr2d[i][j] <&l T ' \ t ';} cout << Endl;}

As you can see, a two-bit array is actually a one-dimensional array whose elements are two-bit arrays

The principle and use of the c++11 array