std::istreambuf_iterator
Defined in header <iterator> |
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|---|---|---|
template< class CharT, class Traits = std::char_traits<CharT> >
class istreambuf_iterator : public std::iterator< std::input_iterator_tag,
CharT,
typename Traits::off_type,
/* unspecified, usually CharT* */,
CharT > |
(until C++17) | |
template< class CharT, class Traits = std::char_traits<CharT> > class istreambuf_iterator; |
(since C++17) |
std::istreambuf_iterator is a single-pass input iterator that reads successive characters from the std::basic_streambuf object for which it was constructed.
The default-constructed std::istreambuf_iterator is known as the end-of-stream iterator. When a valid std::istreambuf_iterator reaches the end of the underlying stream, it becomes equal to the end-of-stream iterator. Dereferencing or incrementing it further invokes undefined behavior.
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(since C++11) |
Member types
| Member type | Definition |
|---|---|
iterator_category |
std::input_iterator_tag |
value_type |
CharT |
difference_type |
Traits::off_type |
pointer |
/* unspecified, usually CharT* */ |
reference |
CharT |
char_type |
CharT |
traits_type |
Traits |
int_type |
typename traits::int_type |
streambuf_type |
std::basic_streambuf<CharT, Traits> |
istream_type |
std::basic_istream<CharT, Traits> |
| /* proxy */ | Implementation-defined class type. The name proxy is for exposition only.A proxy object holds a char_type character and a streambuf_type* pointer.Deferencing a proxy object with operator* yields the stored character. |
| Member types |
(until C++17) |
Member functions
constructs a new istreambuf_iterator (public member function) |
|
|
(destructor)
(implicitly declared)
|
destructs an istreambuf_iterator (public member function) |
|
(since C++11)(until C++17)
|
obtains a copy of the current character accesses a member of the current character, if CharT has members (public member function) |
| advances the iterator (public member function) |
|
tests if both istreambuf_iterators are end-of-stream or if both are valid (public member function) |
Non-member functions
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(removed in C++20)
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compares two istreambuf_iterators (function template) |
Example
#include <string>
#include <sstream>
#include <iostream>
#include <iterator>
int main()
{
// typical use case: an input stream represented as a pair of iterators
std::istringstream in{"Hello, world"};
std::istreambuf_iterator<char> it{in}, end;
std::string ss{it, end};
std::cout << "ss has " << ss.size() << " bytes; "
"it holds \"" << ss << "\"\n";
// demonstration of the single-pass nature
std::istringstream s{"abc"};
std::istreambuf_iterator<char> i1{s}, i2{s};
std::cout << "i1 returns '" << *i1 << "'\n"
"i2 returns '" << *i2 << "'\n";
++i1;
std::cout << "after incrementing i1, but not i2\n"
"i1 returns '" << *i1 << "'\n"
"i2 returns '" << *i2 << "'\n";
++i2;
std::cout << "after incrementing i2, but not i1\n"
"i1 returns '" << *i1 << "'\n"
"i2 returns '" << *i2 << "'\n";
}
Output:
ss has 12 bytes; it holds "Hello, world" i1 returns 'a' i2 returns 'a' after incrementing i1, but not i2 i1 returns 'b' i2 returns 'b' after incrementing i2, but not i1 i1 returns 'c' i2 returns 'c'
See also
output iterator that writes to std::basic_streambuf (class template) |
|
input iterator that reads from std::basic_istream (class template) |
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