2.vector数组

• 创建vector数组

   vector<int> myint{ ,,,, };

• 尾部插入

   for (int i = ; i < ; i++)
   {
       myint.push_back(i);
  
   }

• 读取头部和尾部

   cout << myint.front() << endl;
   cout << myint.back() << endl;

• 动态调整大小

   myint.resize();//动态调整大小

• 设置只有六个数据但是缓冲区有90

  myint.resize(, );//设置只有六个数据,但是缓冲有90

• 正向读取

   for (auto ib = myint.begin(), ie = myint.end(); ib != ie; ib++)
   {
       cout << *ib << endl;
   }

• 逆向读取

   for (auto rb = myint.rbegin(), re = myint.rend(); rb != re; rb++)
   {
       cout << *rb << endl;
   }

• 读取

   for (int i = ; i < myint.size(); i++)
   {
       cout << myint[i] << endl;
   }
  
   for (auto i : myint)
   {
       cout << i << endl;
   }

• 重新初始化

   myint.assign(, );

• 根据位置插入

   auto it = myint.begin() + ;
   myint.insert(it, );//根据位置插入

• 插入一个数组

   int a[] = { ,,,, };
   myint.insert(it, a, a + );//插入一个数组

• 插入一个vector

   vector<int> myintX = { ,, };
   //批量插入
   myint.insert(it, myintX.begin(), myintX.end());

• 删除和批量删除

   myint.erase(it);
   myint.erase(myint.begin(), myint.begin() + );//批量删除

• 调用分配器使用自己分配的内存

   //调用分配器
   vector<int> mymem;
   int *p = mymem.get_allocator().allocate();//获取分配器分配内存
   for (int i = ; i < ; i++)
   {
       cout << (p[i] = i) << endl;
   }
   myint.get_allocator().deallocate(p, );//释放内存

• vector嵌套

   　　//vector嵌套
       vector<int> myint1{ ,, };
       vector<int> myint2{ ,, };
       vector<int> myint3{ ,, };
       vector<vector<int>> myallint{ myint1,myint2,myint3 };
       for (auto i : myallint)
       {
           for (auto j : i)
           {
               cout << j << endl;
           }
       }