// Calcolo dell'angolo e della distanza tra due vettori

#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;

int main(){

  double a[3], b[3];
  double ab, na, nb;
  double ang, dist;
  fstream f;

  f.open("vettori.dat",ios::in);
  
  if ( f.fail() ){
    cout << "Errore nell'apertura di 'vettori.dat' ==> Esco" << endl;
    return -1;
  }
  
  f >> a[0] >> a[1] >> a[2] >> b[0] >> b[1] >> b[2];
  
  while( ! f.eof() ){
  
    ab   = 0.;
    na   = 0.;
    nb   = 0.;
    dist = 0.;
    
    cout << "A     B" << endl;
    cout << "-------" << endl;
    for ( int i = 0; i < 3; i++ ){
      cout << a[i] << "     " << b[i] << endl;
      ab   += a[i]*b[i];
      na   += a[i]*a[i];
      nb   += b[i]*b[i];
      dist += (a[i] - b[i])*(a[i] - b[i]);
    }
    na   = sqrt( na );
    nb   = sqrt( nb );
    ang  = acos( ab/(na*nb) );
    dist = sqrt( dist );

    cout << "Angolo   = " << ang  << endl;
    cout << "Distanza = " << dist << endl;
    cout << "-----------" << endl;
    f >> a[0] >> a[1] >> a[2] >> b[0] >> b[1] >> b[2];
  
  }
  f.clear();
  f.close();
  
  return 0;
  
}