///////    File: Vector.C    ///////
#include   <iostream.h>
#include   "Vector.h"

Vector::Vector(Dim n, double* arr)
: v(new double[n]), len(n)
{   for(int i = 0; i < n; i++)
        v[i] = arr[i];
}

double Vector::inner(double* w)
{ double ans = 0;
    for( int i=0 ; i < len ; i++ )
         ans += v[i]*w[i];
    return(ans);
}

Vector::Vector(const Vector& vec)      // copy consstructor
: v(new double[vec.len]), len(vec.len)
{ for( int i = 0; i < len; i++ )
      v[i] = vec.v[i];
}

Vector& Vector::OP = (const Vector& vec)
{  if( &vec == this )
      return(*this);
   if ( len == 0 && vec.len > 0 )
   {  len = vec.len;
      v = new double[len];
   }
   else if ( len != vec.len )
      abort();
   for( int i = 0; i < len; i++ )
      v[i] = vec.v[i];
   return(*this);
}

Vector& Vector::OP += (const Vector& vec)
{  if ( len != vec.len )
      abort();
   cout << "member called\n";
   for( int i = 0; i < len; i++ )
      v[i] += vec.v[i];
   return(*this);
}

Vector& OP += (Vector& v1, const Vector& v2)
{  if ( v1.len != v2.len )
      abort();
   cout << "friend called\n";
   for( int i = 0; i < v1.len; i++ )
      v1.v[i] += v2.v[i];
   return(v1);
}

double& Vector::OP [] (int i)
{   if (i > 0 && i <= len) 
       return(v[i-1]);
    else 
    {  cerr << "Vector index " << i 
            << " out of bounds\n";
       abort();
    }
}

Vector Vector::OP + (const Vector& vec) const
{   if ( len != vec.len )
        abort();
    Vector ans(len);
    for (int i=0; i < len; i++)
        ans.v[i] = v[i] + vec.v[i];
    return(ans);
}

Vector OP * (const Vector& vec, double s)
{   Vector ans(vec.len);
    for (int i=0; i < vec.len; i++)
        ans.v[i] = s  * vec.v[i];
    return(ans);
}


void Vector::display()
{ double *p = v;
  int i = len;
     cout << '(';
     while ( i-- > 0 )
     {    cout << *p++;
          if ( i > 0 ) cout << "  ";
     }
     cout << ")\n";
}

// double arr[] =  {1.5, 2.5, 3.5, 4.5};
// double arr1[] = {1.6, 0.6, 3.6, 4.6};
// double arr2[] = {1.7, 2.7, 3.7, 4.7};