From cppreference.com
constexpriteratorbegin()constnoexcept; (1) (since C++20)constexprconst_iteratorcbegin()constnoexcept; (2) (since C++23)Returns an iterator to the first element of the span.
If the span is empty, the returned iterator will be equal to end().
Return value
Iterator to the first element.
Complexity
Constant.
Example
Run this code
#include<iostream>#include<span>voidprint(std::span<constint>array){std::cout<<"array = ";for(autoit=array.begin();it!=array.end();++it)std::cout<<*it<<' ';std::cout<<'\n';}voidset_first_element(std::span<int>sp,intnew_value){if(!sp.empty()){std::cout<<"old *begin = "<<*sp.begin()<<'\n';*sp.begin()=new_value;std::cout<<"new *begin = "<<*sp.begin()<<'\n';}}intmain(){intarray[]{1,3,4,5};print(array);set_first_element(array,2);print(array);}Output:
array = 1 3 4 5 old *begin = 1 new *begin = 2 array = 2 3 4 5 See also
(C++23)
returns an iterator to the end
(public member function)
(C++11)(C++14)
returns an iterator to the beginning of a container or array
(function template)