operator<<(std::basic_string_view)

 

C++

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Named requirements

Feature test macros(C++20)

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Technical specifications

Symbols index

External libraries

 

Strings library

Classes

basic_string

basic_string_view (C++17)

char_traits

 

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)

 

Defined in header <string_view>
template<class CharT, class Traits > std::basic_ostream<CharT, Traits>&     operator<<(std::basic_ostream<CharT, Traits>& os,                 std::basic_string_view<CharT, Traits> v );		(since C++17)

Behaves as a FormattedOutputFunction. After constructing and checking the sentry object, determines the output format padding.

Then stores each character from the resulting sequence seq (the contents of v with padding) to the output stream os as if by calling os.rdbuf()->sputn(seq, n), where n is std::max(os.width(), str.size()).

Finally, calls os.width(0) to cancel the effects of std::setw, if any.

Exceptions

May throw std::ios_base::failure if an exception is thrown during output.

Parameters

os	-	a character output stream
v	-	the view to be inserted

Return value

os

Example

Run this code

#include <iomanip>#include <iostream>#include <string_view>   int main(){constexprstd::string_view s{"abc"};constexprint width{5};   // fill/left/right properties are kept until changedstd::cout<<std::setfill('-');std::cout<<std::left;   std::cout<<'['<<std::setw(width)<< s <<"]\n";std::cout<<'['<<std::setw(width)<< s <<"]\n";   std::cout<<std::right;std::cout<<'['<<std::setw(width)<< s <<"]\n";   // width is reset after each callstd::cout<<'['<< s <<"]\n";}

Output:

[abc--] [abc--] [--abc] [abc]

See also

operator<<operator>>

performs stream input and output on strings (function template)