/******************************************************************************
* test macro to sort two columns                
******************************************************************************/

///////////////////////////
// To run it in root: 
//     > .L DoubleSort.C+ 
//     > DoubleSort("table4test.txt")
//
///////////////////////////


#include <Riostream.h>

#include "TMath.h"
#include "TString.h"

const Int_t kBufSize  = 1024;


void DoubleSort(const char *infile, const char *sep = "\t")
{
   ifstream input;
   input.open(infile, ios::in);
   if (!input.good()) {
      cerr << "Error: File does not exist: " << infile << endl;
      input.close();
      return;
   }//if

   char nextline[512];

   Int_t fN = 9;
   Int_t *x = new Int_t[fN];
   Int_t *y = new Int_t[fN];

   Long64_t *w      = new Long64_t[fN];
//?   Long64_t *fIndex = new Long64_t[fN];
   Int_t    *fIndex = new Int_t[fN];

   Int_t idx = 0;
   while (input.good()) {
      input.getline(nextline, kBufSize, '\n');
      if (input.eof()) break;

      x[idx] = atoi(strtok(&nextline[0], sep));
      y[idx] = atoi(strtok(0, sep));

      Long64_t majorv = (Long64_t)x[idx];
      Long64_t minorv = (Long64_t)y[idx];
      w[idx]  = majorv << 31;
      w[idx] += minorv;
cout << "x = " << majorv <<  "   y = " << minorv <<  "   w[i] = " << w[idx] << endl;
      idx++;
   }//while

   TMath::Sort(fN, w, fIndex, 0);

   for (Int_t i=0; i<fN; i++) {
      cout << "x = " << x[fIndex[i]] <<  "  y = " << y[fIndex[i]] << "   fIndex[i] = " << fIndex[i] << endl;
   }

   delete [] fIndex;
   delete [] w;
   delete [] y;
   delete [] x;

   input.close();
}//DoubleSort