#include <iostream>
#include <iterator>
#include <vector>
 
struct line : std::string 
{
    friend std::istream & operator >> (std::istream & in, line & ln)
    {
        return std::getline(in, ln);
    }
};
 
int main() {
    std::istream_iterator<line> begin(std::cin), end;
    std::vector<std::string> allLines(begin, end);
 
    std::cout << allLines.size() << " lines read from file, and they're :" << std::endl;
    std::copy(allLines.begin(), allLines.end(),
          std::ostream_iterator<std::string>(std::cout, "\n"));
    return 0;
}

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V291bGQgCkBOYXdheidzIGFuc3dlciAKd29yayBvbiBjaW4uClllcywgYW5kIHRoZXkgd291bGQuCkFuZCBoZXJlIGlzIHRoZSBwcm9vb2YgOi0p

Would 
@Nawaz's answer 
work on cin.
Yes, and they would.
And here is the prooof :-)