#include <vector>
#include <iostream>
#include <string>
#include <fstream>
#include <time.h>
#include <numeric> 
#include <cmath>
#include "mySTD.h"

using namespace std;

int main () {

  // create a small vector pushing back numbers

  vector<double> data_small;

  data_small.push_back(2.);
  data_small.push_back(3.);
  data_small.push_back(4.);
  data_small.push_back(5.);
  
  // compute average and variance through templace functions
  
  cout << mySTD::myAve(data_small.begin() , data_small.end() ) << endl;
  cout << mySTD::myVar(data_small.begin() , data_small.end() ) << endl;

  // loop over vector elements

  for( int k = 0 ; k < data_small.size() ; k++) {
    cout << "Value ==>> " << data_small[k] << endl;
  }
  
  // loop over vector elements using iterators

  for( vector<double>::iterator myIt = data_small.begin(); myIt != data_small.end(); myIt++) {
    cout << "Value ==>> " << *myIt << endl;
  }
 
  // create a vector and read elements from file
  
  // 1 - the naive way

  int N = 1000000;
  string filename = "data.txt";
  
  vector<double> data_to_read ;
  
  mySTD::ReadVector( filename  , N , data_to_read );

  // 2 - the professional way 

  ifstream inputFile(filename);
  std::vector<double> data((std::istream_iterator<double>(inputFile)),std::istream_iterator<double>());   
  inputFile.close();

  // print the vector elements to stdin using the function copy

  ostream_iterator< double > output( cout, "\n" );
  copy( data.begin(), data.end(), output );
 
  // print to file usign the function copy

  ofstream fileout("test.test");
  ostream_iterator< double > output_file( fileout, "\n" );
  copy( data.begin(), data.end(), output_file );

  // print vector using a function 
  
  mySTD::print( data.begin() , data.end() );

  // now use an algorithm in the STL to sort elements

  clock_t t = clock();
  
  sort(data.begin(), data.end());

  t = clock() - t;

  float elapsed_time = ((float)t)/CLOCKS_PER_SEC;

  cout << "It took me seconds " << elapsed_time  << " to sort " << N << " elements" << endl;

  // now compute the mean and variance using functions
  
  cout << mySTD::myAve(data.begin(), data.end() ) << endl;
  cout << mySTD::myVar(data.begin(), data.end() ) << endl;

  // or even better use accumulators from STL

  double sum = std::accumulate(data.begin(), data.end(), 0.0);
  double mean = sum / data.size();
  
  double sq_sum = std::inner_product(data.begin(), data.end(), data.begin(), 0.0);
  double stdev = std::sqrt(sq_sum / data.size() - mean * mean);

  // or use BOOST functions
  
  /*
    accumulator_set<double, stats<tag::variance> > acc;
    for_each(a_vec.begin(), a_vec.end(), bind<void>(ref(acc), _1));
    
    cout << mean(acc) << endl;
    cout << sqrt(variance(acc)) << endl;
  */

}