Input from file & FOR loop

I am a newbie working on a problem that will perform various mathematical functions. My problem is I would like to know how to read in values from a file using FOR loops. I need to read in the number of values followed by the sequence of values. (I've been playing around with this for over a week and just need some help to get the ball rolling.) Thanks in advance!

Could you give an example of what your datafile looks like.

Roughly (may be problems, but here's an idea)

Code:

---


#include <fstream>
using namespace std;

void processFile(string filename)
{
    ifstream f(filename);

    vector<double> values;

    int count;
    f >> count;
    for( int i = 0; i < count; ++i )
    {
          double val;
          f >> val;
          values.push_back(val);
    }
}

---

Jeff

Just an idea

Code:

---

#include <fstream>

using namespace std;

int main()
{
  ifstream is("input");

  if ( ! is )
    return 1; // error opening
 
  while ( is.good() )
  {
    int count;
    for ( is >> count; is.good() && count; count-- )
    {
      double d;
      is >> d;
      // do something creative here
    }
    if ( count )
      return 2; // error too few values
  }

        return 0;
}

---

The input file may look like this:

Code:

---

4 1.2 3.4 5.6 6.7
2
1.2
1.3

---

Regards,