getline vs istream_iterator

问题:

Should there be a reason to preffer either getline or istream_iterator if you are doing line by line input from a file(reading the line into a string, for tokenization).

回答1:

I sometimes (depending on the situation) write a line class so I can use istream_iterator:

#include <string>
#include <vector>
#include <iterator>
#include <iostream>
#include <algorithm>

struct Line
{
    std::string lineData;

    operator std::string() const
    {
        return lineData;
    }
};
std::istream& operator>>(std::istream& str,Line& data)
{
    std::getline(str,data.lineData);
    return str;
}

int main()
{
     std::vector<std::string>    lines;
     std::copy(std::istream_iterator<Line>(std::cin),
               std::istream_iterator<Line>(),
               std::back_inserter(lines)
              );
}

回答2:

getline will get you the entire line, whereas istream_iterator<std::string> will give you individual words (separated by whitespace).

Depends on what you are trying to accomplish, if you are asking which is better (tokenization is just one bit, e.g. if you are expecting a well formed program and you expect to interpret it, it may be better to read in entire lines...)