size_t size()constnoexcept;constT* begin()constnoexcept;constT* end()constnoexcept; 通过std::initializer_list<T>可以实现大括号初始化对象。也可以实现类似于动态类型的效果。 1#include <iostream>2#include <initializer_list>3#include <vector>45usingnamespacestd;67classTest {8vector<int>list;9pub...
());}std::pair<constT*,std::size_t>c_arr()const{return{&v[0], v.size()};// 在 return 语句中进行复制列表初始化// 没有使用 std::initializer_list}};template<typenameT>voidtemplated_fn(T){}intmain(){S<int>s={1,2,3,4,5};// 复制列表初始化s.append({6,7,8});// 在函数...
它的实现很简单本质是就是一个指针和一个数组长度组成,源码如下: template<class_E>classinitializer_list{public:typedef_Evalue_type;typedefconst_E&reference;typedefconst_E&const_reference;typedefsize_tsize_type;typedefconst_E*iterator;typedefconst_E*const_iterator;private:iterator_M_array;size_type_M_le...
constexprsize_type size()constnoexcept; (since C++14) Returns the number of elements in the initializer list, i.e.std::distance(begin(), end()). Parameters (none) Return value the number of elements in the initializer list Complexity ...
我希望只有一个模板函数。所以我想到了像这样的..。template<typename Iteratable, size_t N, typename = std::enable_if_t< std::is_same_v<Iteratable, const std::initializer_list<size_t> > ||
template<std::size_t POS> constexpr auto get(const CONVERTED&_r) { constexpr auto &r = s_original2Compressed.begin()[POS]; return get<r.second.first, r.second.second>(_r, std::integral_constant<bool, r.first>()); } static constexpr double v0 = 1.0; ...
汉字的表示就要用到wchar_t 。char，我们都知道，占一个字节，8位宽。 标准C++中的wprintf()函数以及...
..args){std::vector<V>vec;vec.reserve(sizeof...(Args));usingarr_t=int[];(void)arr_t{0...
constT*end()constnoexcept; (since C++11) (until C++14) constexprconstT*end()constnoexcept; (since C++14) Returns a pointer to one past the last element in the initializer list, i.e.begin()+size(). If the initializer list is empty, the values ofbegin()andend()are unspecified, but...
Note that we cannot do the same withstd::arrayas the parameter to a function would have to have a fixed size.initializer_listhas a variable length; the compiler takes care of that. Moreover, the “internal” array is created on the stack, so it doesn’t require any additional memory al...