Re: reading from a file
On Oct 8, 4:18 pm, Joshua Maurice <joshuamaur...@gmail.com> wrote:
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
posthttp://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/refer=
ence/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/i=
terator/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 withhttp://www.comea=
ucomputing.com/tryitout/
It has not been tested to produce correct results at runtime.
thanks Joshua Maurice for the code. I wrote a non compiling code
because, I could not figure it out how to make it compile. I quickly
realised that there is no begin()/end() methods but then I was just
lost there. After using the copy algorithm for displaying contents of
containers on cout, I guessed that there must be a way to do the same
for input also. I tested your code and its working fine. thanks again
suresh