#include<iostream>#include<set>intmain(){std::set<int>my_set={1,2,3,4,5};// 获取第一个元素的迭代器std::set<int>::iterator it=my_set.begin();// 输出第一个元素std::cout<<"First element: "<<*it<<std::endl;// 遍历set中的所有元素for(it=my_set.begin();it!=my_set.end()...
C++ std::set 取第一个元素 #include <iostream> #include <set> using namespace std; int main() { // cbegin/cend(c++11): Returns a const_iterator pointing to the first element in the container/ // Returns a const_iterator pointing to the past-the-end element in the container std::set...
set.end(),[&out](constT&element){out<<", "<<element;});returnout<<" }";}intmain(){std::set<int>set{1,5,3};std::cout<<set<<'\n';set.insert(2);std::cout<<set<<'\n';set.erase(1);std::cout<<set<<"\n\n";std::set<int>keys{3,4};for(intkey:keys){if(set.cont...
unordered_set的emtpy()实现也是判断size()==0。而size()返回的是内部维护的私有变量M_element_count。
lambda 表达式或函数对象），它接受一个元素作为参数，并返回一个可以转换为bool的值。如果p(element)为...
// construct smuggled allocator_arg_t element } template<class... _Other, class = typename _Tuple_enable< tuple<const _Other&...>, _Myt>::type> tuple(const tuple<_Other...>& _Right) : _Mybase(_Right._Get_rest()), _Myfirst(_Right._Myfirst._Val) ...
std::basic_streambuf::setg std::basic_streambuf::setp std::basic_streambuf::sgetc std::basic_streambuf::sgetn std::basic_streambuf::showmanyc std::basic_streambuf::snextc std::basic_streambuf::sputbackc std::basic_streambuf::sputc std::basic_streambuf::sputn std::basic_streambuf:...
{// deque::at: Returns a reference to the element at a specified location in the deque. usingnamespacestd; deque <int> c1; c1.push_back(10); c1.push_back(20); constint& i = c1.at(0); int& j = c1.at(1); cout <<"The first element is " << i <<endl; ...
std::set::insert C++98 C++11 single element (1) pair<iterator,bool> insert (const value_type& val); with hint (2) iterator insert (iterator position, const value_type& val); range (3) template <class InputIterator> void insert (InputIterator first, InputIterator last); ...
In a set, the value of an element also identifies it (the value is itself the key, of type T), and each value must be unique. The value of the elements in a set cannot be modified once in the container (the elements are always const), but they can be inserted or removed from th...