C++ Iterator Library - istreambuf_iterator

Description

It is a special input iterator that read successive elements from a stream buffer.

Declaration

Following is the declaration for std::istreambuf_iterator.

C++11

template <class charT, class traits = char_traits<charT> >
  class istreambuf_iterator;

Parameters

• charT − It is a char type.

• traits − It is a character traits.

Return value

none

Exceptions

If x somehow throws while applying the unary operator& to it, this function never throws exceptions.

Time complexity

constant for random-access iterators.

Example

The following example shows the usage of std::istreambuf_iterator.

#include <vector>
#include <sstream>
#include <iostream>
#include <iterator>
 
int main() {

   std::istringstream in("Hello, world");
   std::vector<char> v( (std::istreambuf_iterator<char>(in)),
                         std::istreambuf_iterator<char>() );
   std::cout << "v has " << v.size() << " bytes. ";
   v.push_back('\0');
   std::cout << "it holds \"" << &v[0] << "\"\n";

   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';
 
}

Let us compile and run the above program, this will produce the following result −

v has 12 bytes. it holds "Hello, world"
i1 returns a
i2 returns a
after incrementing i1, but not i2
i1 returns b
i2 returns a
after incrementing i2, but not i1
i1 returns b
i2 returns c