#include <fstream>    
using namespace std;

// Contract: char[] double[] int& -> bool
// Purpose: try to open the file named fname for reading,
//          which is expected to contain an integer
//          number of rats' weights, followed by that
//          many rats' weights expressed as doubles.
//          Initialize ratWts to be an array of that
//          many rats' weights, store those rats' weights
//          into it, and change the argument corresponding
//          to numWts to contain the number of rats'
//          weights.
//
//          Returns false if cannot open fname for reading;
//          returns true if it can. 
//
// Examples: if a file in the current directory named
//           ratWeights.txt contains the following:
// 4
// 13.3
// 5
// 27.1
// 15.5
//           ...then 
//           wtsIntoArray("ratWeights.txt", allWts, howMany)
//              == true,
//           and howMany should be set to 4,
//           and allWts[0] == 13.3
//               allWts[1] == 5
//               allWts[2] == 27.1
//               allWts[3] == 15.5 
//
// by: Sharon M. Tuttle
// last modified: 10-29-03

bool wtsIntoArray(const char fname[], 
                  double ratWts[], int& numWts)
{
    // local variables
    ifstream input_stream;

    // can you open specified file for reading?
    input_stream.open(fname);
    if (input_stream.fail())
    {
        // this is not a main function! So, exit(1) not
        //    appropriate.
        // returning a value of false IS appropriate, tho
        return false;
    }
    
    // IF reach here --- we DID successfully open the
    //    file.
    
    // how many rats' weights are there?
    input_stream >> numWts;

    // ...and now try to FILL ratWts with that many
    //    weights...
    for (int i=0; i < numWts; i++)
    {
        input_stream >> ratWts[i];
    }

    // if get here --- clean up and return true
    input_stream.close();
    return true;
}