Re: reading from a file
On Oct 7, 3:38 pm, suresh <suresh.amritap...@gmail.com> wrote:
Hi,
I wrote a code like this and it failed to read from file. My question
what is the shortest code to read from a file and populate a vector?
vector<double> d;
ifstream in("myfile.txt");
copy(in.begin(),in.end(),back_inserter(d));
For starters, your code does not compile. Please see the FAQ on how to
post
http://www.parashift.com/c++-faq-lite/
Specifically please post complete compile-able examples. If you do not
know enough to post a complete compilable example, then do the closest
that you can. In the process of trying to make it compile (and work),
you might learn it on your own.
ifstream has no member functions begin and end.
http://cplusplus.com/reference/iostream/ifstream/
If you want to treat a std::istream as a readable sequence ala
iterators, see std::istream_iterator.
http://cplusplus.com/reference/std/iterator/istream_iterator/
A complete example would be:
#include <algorithm>
#include <fstream>
#include <functional>
#include <iterator>
#include <vector>
using namespace std;
int main()
{
vector<double> d;
ifstream in("myfile.txt");
copy(
istream_iterator<double>(in),
istream_iterator<double>(),
back_inserter(d)
);
}
Disclaimer: the code has only been tested to compile with
http://www.comeaucomputing.com/tryitout/
It has not been tested to produce correct results at runtime.