#include <iostream>
using namespace std;

class Niz {
    unsigned _duzina;
    unsigned _obezbedjeno;
    int* _elementi;

    void ispis( ostream& ostr ) const
        {
        ostr << '[' << _duzina << ':';
        for( unsigned i=0; i<_duzina; i++ )
            ostr << _elementi[i] << ',';
        ostr << "\b]";
        }

    friend ostream& operator << (ostream&,const Niz&);
            

    void povecanjeNiza( unsigned n )
        {
        if( n <= _duzina )
            return;
        if( n > _obezbedjeno )
	   {
            unsigned ob = n;
            int pomocna = _duzina*2;
            if( pomocna > ob )
                 ob = pomocna;
            
	    int* novi = new int[ob];
            for( unsigned i=0; i<_duzina; i++ )
                novi[i] = _elementi[i];
            delete [] _elementi;
            _elementi = novi;

            _obezbedjeno = ob;
            }



        for( unsigned i=_duzina; i<n; i++ )
            _elementi[i] = 0;
        _duzina = n;
        }



public:
    Niz()
        : _duzina(0),
          _obezbedjeno(0),
          _elementi(0)
        {}

    ~Niz()
        {
        delete [] _elementi;
        }

    Niz(const Niz& n)
        : _duzina(n._duzina),
          _obezbedjeno(n._duzina),
          _elementi( n._duzina>0 ? new int[n._duzina] : 0 )
                
        {
        for( unsigned i=0; i<_duzina; i++ )
            _elementi[i] = n._elementi[i];
        }



    Niz& operator = (const Niz& n)
        {
        if( this != &n ){
            delete [] _elementi;
            _duzina = n._duzina;
            _obezbedjeno = n._duzina;
            _elementi = n._duzina>0 ? new int[n._duzina] : 0;
            for( unsigned i=0; i<_duzina; i++ )
            _elementi[i] = n._elementi[i];
            }
        return *this;
        }



    int& operator [] (unsigned i) 
        {
        if( i >= _duzina )
            povecanjeNiza( i+1 );
        return _elementi[i];
        }


     int operator[] ( unsigned i ) const
        {
        if( i >= _duzina )
            throw "Neispravan indeks niza!";
        return _elementi[i];
        }
};



ostream& operator << (ostream& ostr, const Niz& n )
        
{
    n.ispis(ostr);
    return ostr;
}



main() 
{
    Niz a;
    a[4] = 3;
    a[2] = 2;

    Niz b(a);
    b[3] = 7;
    b[5] = 8;

    cout << "a:" << a << endl;
    cout << "b:" << b << endl;

    a[7]=2;
    cout << "a:" << a << endl;

    for( unsigned i=0; i<10; i++ )
	{
        Niz q;
        for( unsigned j=0; j<1000000; j++ )
            q[j]=j;
        }

    //moze efikasnije!!!
    for( unsigned i=0; i<10; i++ )
	{
        Niz q;
        for( unsigned j=1000000; j>=1; j-- )
            q[j]=j;
        }

    return 0;
}