std::vector::vector
STD：：向量：
| | (1) | |
|---|---|---|
| explicit vector( const Allocator& alloc = Allocator() | (until C++14) | |
| vector() : vector( Allocator() ) {} explicit vector( const Allocator& alloc | (since C++14) (until C++17) | |
| vector() noexcept(noexcept(Allocator())): vector( Allocator() ) {} explicit vector( const Allocator& alloc ) noexcept; | (since C++17) | |
| | (2) | |
| explicit vector( size_type count, const T& value = T(), const Allocator& alloc = Allocator() | (until C++11) | |
| vector( size_type count, const T& value, const Allocator& alloc = Allocator() | (since C++11) | |
| | (3) | |
| explicit vector( size_type count | (since C++11) (until C++14) | |
| explicit vector( size_type count, const Allocator& alloc = Allocator() | (since C++14) | |
| template< class InputIt > vector( InputIt first, InputIt last, const Allocator& alloc = Allocator() | (4) | |
| vector( const vector& other | (5) | |
| vector( const vector& other, const Allocator& alloc | (5) | (since C++11) |
| | (6) | |
| vector( vector&& other | (since C++11) (until C++17) | |
| vector( vector&& other ) noexcept; | (since C++17) | |
| vector( vector&& other, const Allocator& alloc | (7) | (since C++11) |
| vector( std::initializer_list<T> init, const Allocator& alloc = Allocator() | (8) | (since C++11) |
从各种数据源构造一个新容器，可以选择使用用户提供的分配器。alloc...
1%29默认构造函数。构造空容器。
2%29用count具有价值的元素的副本value...
3%29用count默认插入实例T.不制作副本。
4%29构造包含范围内容的容器。[first, last)...
| This constructor has the same effect as vector(static_cast | (until C++11) |
|---|---|
| This overload only participates in overload resolution if InputIt satisfies InputIterator, to avoid ambiguity with the overload (2). | (since C++11) |
5%29复制构造函数。的内容的副本构造容器。other.如果alloc如果不提供分配器，则获得分配器时，就像通过调用std::allocator_traits<allocator_type>::select_on_container_copy_construction(other.get_allocator())...
6%29移动构造函数。的内容构造容器。other使用移动语义。分配器是通过移动构造从分配器获得的，该分配器属于other...
7%29分配器-扩展移动构造函数。使用alloc作为新容器的分配器，将内容从other；如果alloc != other.get_allocator()，这就导致了一个元素上的移动。
8%29使用初始化程序列表的内容构造容器。init...
参数
| alloc | - | allocator to use for all memory allocations of this container |
|---|---|---|
| count | - | the size of the container |
| value | - | the value to initialize elements of the container with |
| first, last | - | the range to copy the elements from |
| other | - | another container to be used as source to initialize the elements of the container with |
| init | - | initializer list to initialize the elements of the container with |
复杂性
1%29常数
2-3%29线性count
4%29直线距离first和last
5%29线性other
6%29常数。
7%29线性IFalloc != other.get_allocator()，否则不变。
8%29线性init...
注记
在容器移动构造%28重载%286%29%29之后，引用、指针和迭代器%28---other保持有效，但引用当前在*this.现行标准通过第23.2.1节中的总括声明作出这一保证。集装箱。所需经费/12，目前正在考虑通过以下方式提供更直接的担保：lwg 2321...
重载%283%29从非类类型的元素(如int，这与new[]，这使得它们没有初始化。与…的行为相匹配new[]，一自定义分配器：：构造可以提供这样的元素，而这些元素没有初始化。
例
二次
#include <vector>
#include <string>
#include <iostream>
template<typename T>
std::ostream& operator<<(std::ostream& s, const std::vector<T>& v) {
s.put('['
char comma[3] = {'\0', ' ', '\0'};
for (const auto& e : v) {
s << comma << e;
comma[0] = ',';
}
return s << ']';
}
int main()
{
// c++11 initializer list syntax:
std::vector<std::string> words1 {"the", "frogurt", "is", "also", "cursed"};
std::cout << "words1: " << words1 << '\n';
// words2 == words1
std::vector<std::string> words2(words1.begin(), words1.end()
std::cout << "words2: " << words2 << '\n';
// words3 == words1
std::vector<std::string> words3(words1
std::cout << "words3: " << words3 << '\n';
// words4 is {"Mo", "Mo", "Mo", "Mo", "Mo"}
std::vector<std::string> words4(5, "Mo"
std::cout << "words4: " << words4 << '\n';
}
二次
产出：
二次
words1: [the, frogurt, is, also, cursed]
words2: [the, frogurt, is, also, cursed]
words3: [the, frogurt, is, also, cursed]
words4: [Mo, Mo, Mo, Mo, Mo]
二次
另见
| assign | assigns values to the container (public member function) |
|---|---|
| operator= | assigns values to the container (public member function) |
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