std::operator<<,>>

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

char_traits

 

std::basic_string

Member functions

basic_string::basic_string

basic_string::operator=

basic_string::assign

basic_string::get_allocator

Element access

basic_string::at

basic_string::operator[]

basic_string::front (C++11)

basic_string::back (C++11)

basic_string::data

basic_string::c_str

Iterators

basic_string::begin basic_string::cbegin (C++11)

basic_string::end basic_string::cend (C++11)

basic_string::rbegin basic_string::crbegin (C++11)

basic_string::rend basic_string::crend (C++11)

Capacity

basic_string::empty

basic_string::size

basic_string::length

basic_string::max_size

basic_string::reserve

basic_string::capacity

basic_string::shrink_to_fit (C++11)

Operations

basic_string::clear

basic_string::insert

basic_string::erase

basic_string::push_back

basic_string::pop_back (C++11)

basic_string::append

basic_string::operator+=

basic_string::compare

basic_string::replace

basic_string::substr

basic_string::copy

basic_string::resize

basic_string::swap

Search

basic_string::find

basic_string::rfind

basic_string::find_first_of

basic_string::find_first_not_of

basic_string::find_last_of

basic_string::find_last_not_of

Constants

basic_string::npos

Non-member functions

operator+

operator== operator!= operator< operator> operator<= operator>=

swap(std::basic_string)

operator<< operator>>

getline

stoi stol stoll (C++11) (C++11) (C++11)

stoul stoull (C++11) (C++11)

stof stod stold (C++11) (C++11) (C++11)

to_string (C++11)

to_wstring (C++11)

Helper classes

hash<std::string> hash<std::wstring> hash<std::u32string> hash<std::u16string> (C++11)

 

Defined in header <string>
template <class CharT, class Traits, class Allocator> std::basic_ostream<CharT, Traits>&     operator<<(std::basic_ostream<CharT, Traits>& os,                const std::basic_string<CharT, Traits, Allocator>& str);	(1)
template <class CharT, class Traits, class Allocator> std::basic_istream<CharT, Traits>&     operator>>(std::basic_istream<CharT, Traits>& is,                std::basic_string<CharT, Traits, Allocator>& str);	(2)

1) Behaves as an FormattedOutputFunction. After constructing and checking the sentry object, determines the output format padding in the same manner as stage 3 of num_put::put().

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

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

2) Behaves as an FormattedInputFunction. After constructing and checking the sentry object, which may skip leading whitespace, first clears str with str.erase(), then reads characters from is and appends them to str as if by str.append(1, c), until one of the following conditions becomes true:

• N characters are read, where N is is.width() if is.width() > 0, otherwise N is str.max_size()
• the end-of-file condition occurs in the stream is
• std::isspace(c,is.getloc()) is true for the next character c in is (this whitespace character remains in the input stream).

If no characters are extracted then std::ios::failbit is set on is, which may throw std::ios_base::failure.

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

Exceptions

1) may throw std::ios_base::failure if an exception is thrown during output.

2) may throw std::ios_base::failure if no characters are extracted from is (e.g the stream is at end of file, or consists of whitespace only), or if an exception is thrown during input.

Parameters

os	-	a character output stream
is	-	a character input stream
str	-	the string to be inserted or extracted

Return value

1) os

2) is

Example

run this code

#include <iostream>
#include <string>
 
int main()
{
    std::string greeting = "Hello, whirled!"
    std::cout << greeting << '\n';
}

Output:

Hello, whirled!