#include <iostream>
using namespace std;

// In case this header files included multiple times.
#ifndef _VECTOR_H_INCLUDED
#define _VECTOR_H_INCLUDED

class vector {
   friend ostream &operator<<(ostream &, vector &v);
private:
   double *entries;
   unsigned int N;
public:
   vector (unsigned int Size=2);
   vector (const vector &v); // Arg must be passed by value. Why?
   ~vector(void);

   vector &operator=(const vector &b); // overload assignment operator

   const unsigned int size(void) {return N;};
   double geti (unsigned int i);
   void seti (unsigned int i, double x);

   vector operator+(vector b);
   vector operator-(vector b); // binary
   vector operator-(void); // unary

   void print(void);
   double norm(void); // Compute the 2-norm of a vector
   void zero(); // Set entries of vector to zero.
};

#endif