std::basic_string_view<CharT,Traits>::at

 

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basic_string

basic_string_view (C++17)

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std::basic_string_view

Member functions basic_string_view::basic_string_view    basic_string_view::operator= Iterators basic_string_view::beginbasic_string_view::cbegin basic_string_view::endbasic_string_view::cend basic_string_view::rbeginbasic_string_view::crbegin basic_string_view::rendbasic_string_view::crend Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Operations basic_string_view::copy basic_string_view::substr basic_string_view::compare basic_string_view::starts_with (C++20) basic_string_view::ends_with (C++20) basic_string_view::contains (C++23) basic_string_view::find basic_string_view::rfind basic_string_view::find_first_of basic_string_view::find_last_of basic_string_view::find_first_not_of basic_string_view::find_last_not_of

Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap Constants basic_string_view::npos Non-member functions operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) operator<< operator""sv Helper classes hash<std::string_view>hash<std::wstring_view>hash<std::u8string_view>hash<std::u16string_view>hash<std::u32string_view> (C++20) Deduction guides(C++20)

 

constexpr const_reference at( size_type pos )const;		(since C++17)

Returns a const reference to the character at specified location pos. Bounds checking is performed, exception of type std::out_of_range will be thrown on invalid access.

Parameters

pos

-

position of the character to return

Return value

Const reference to the requested character.

Exceptions

Throws std::out_of_range if pos >= size().

Complexity

Constant.

Example

Run this code

#include <iostream>#include <stdexcept>#include <string_view>   int main(){std::string_view str_view("abcdef");   try{for(std::size_t i =0;true;++i)std::cout<< i <<": "<< str_view.at(i)<<'\n';}catch(conststd::out_of_range& e){std::cout<<"Whooops. Index is out of range.\n";std::cout<< e.what()<<'\n';}}

Possible output:

0: a 1: b 2: c 3: d 4: e 5: f 6: Whooops. Index is out of range. basic_string_view::at: __pos (which is 6) >= this->size() (which is 6)

See also

operator[]	accesses the specified character (public member function)
at	accesses the specified character with bounds checking (public member function of std::basic_string<CharT,Traits,Allocator>)