public member function
<iterator>
| default (1) | istream_iterator(); |
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| initialization (2) | istream_iterator (istream_type& s); |
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| copy (3) | istream_iterator (const istream_iterator& x); |
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| default (1) | istream_iterator(); // constexpr if value_type is literal type |
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| initialization (2) | istream_iterator (istream_type& s); |
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| copy (3) | istream_iterator (const istream_iterator& x) = default; |
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Construct istream iterator
Constructs an istream_iterator object:
- (1) default constructor
- Constructs an end-of-stream istream iterator.
- (2) initalization constructor
- Constructs an istream iterator that is associated with stream s (the object does not own or copy the stream, only stores a reference).
The constructor may automatically attempt to extract an element from s, or defer such an operation until it is dereferenced for the first time.
- (3) copy constructor
- Constructs an istream iterator, with the same istream reference and current value (it does not attempt to extract an additional element on construction).
Parameters
- s
- A stream object, which is associated to the iterator.
Member type istream_type is the type of such stream (defined as an alias of basic_istream<charT,traits>, where charT and trais are the second and third class template parameters).
- x
- An iterator of the same istream_iterator type, whose state is copied.
Example
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// istream_iterator example
#include <iostream> // std::cin, std::cout
#include <iterator> // std::istream_iterator
int main () {
double value1, value2;
std::cout << "Please, insert two values: ";
std::istream_iterator<double> eos; // end-of-stream iterator
std::istream_iterator<double> iit (std::cin); // stdin iterator
if (iit!=eos) value1=*iit;
++iit;
if (iit!=eos) value2=*iit;
std::cout << value1 << "*" << value2 << "=" << (value1*value2) << '\n';
return 0;
}
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Possible output:
Please, insert two values: 120 200
120*200=24000
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