c++之array笔记

说明:以下代码源自vs2019

template  //模板,
class array {
    ....
    
    _Ty _Elems[_Size]; //本质是数组,数组大小固定为Size;
};

(a) void fill(const _Ty& _Value);

fill_n(_Elems, _Size, _Value);//将数组中所有元素值均用_Value代替;

(b) void swap(array& _Other);

array arr = {"I","Love","Liu","xiao","Li"};
array arr1 = {"12","23","34"};
arr1.swap(arr); //要求arr1和arr的大小相等,否则语法错; 即size=5一样,值可以不一样;

for (size_t i = 0; i < arr.size(); i++) {
    cout << arr[i].c_str() << endl; //12 23 34
}

(c) _Ty* _Unchecked_begin();

{
    return _Elems; //返回数组名; 也是首元素地址;
}

(d) _Ty* _Unchecked_end() noexcept 
       

{
    return _Elems + _Size; //返回数组最后一个位置
}

测试:

array arr = {"I","Love","Liu","xiao","Li"};
cout << &arr.at(0) << endl;            //006FFE08
cout << arr._Unchecked_begin() << endl;//006FFE08

cout << &arr.at(4) << endl;            //0093F854
cout << arr._Unchecked_end() << endl;  //0093F870 

&arr.at(4)与arr._Unchecked_end()相差12;恰好是字符串"Li"的长度;

(e) size_type size() 和 size_type max_size() ;

{
    return _Size; //两者均返回元素个数;
}