#include <iostream.h>

#include <conio.h>

#include <assert.h>

class vecto{

public:

vecto(int n=100);// constructor tao mot vecto co do dai n

vecto( const vecto &);//copy constructor

~vecto(); //destructor

friend vecto operator+ ( const vecto &, const vecto &);

friend vecto operator- ( const vecto &, const vecto &);

friend vecto operator* ( const vecto &, const int &);

vecto &operator=(const vecto &);

friend istream &operator >>( istream &, vecto &);

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

int &operator []( int );

int get_num();

private:

int num,*p;

};

vecto::vecto(int n)

{

num=n;

p=new int[num];

for ( int i=0; i<n; i++) p[i]=0;

}

vecto::vecto(const vecto &a)

{

num=a.num;

p= new int[num];

assert(p!=0);

for( int i=0; i<num; i++) p[i]=a.p[i];

}

vecto::~vecto()

{

delete [] p;

}

int vecto::get_num()

{

return num;

}

vecto operator+(const vecto &a, const vecto &b)

{

vecto result;

result.num= (a.num > b.num) ? a.num :b.num;

delete [] result.p;

result.p= new int[result.num];

assert(result.p!=0);

for(int i=0; i< result.num ; i++) result.p[i]=a.p[i]+b.p[i];

return result;

}

vecto operator-( const vecto &a, const vecto &b)

{

vecto result;

result.num= (a.num > b.num) ? a.num :b.num;

delete [] result.p;

result.p= new int[result.num];

assert(result.p!=0);

for(int i=0; i< result.num ; i++) result.p[i]=a.p[i]-b.p[i];

return result;

}

vecto operator*( const vecto &a,const int &n) // nhan vecto a voi mot so nguyen

{

vecto result(a);// saochep

for( int i=0; i<a.num; i++) result.p[i]=a.p[i]*n;

return result;

}

vecto& vecto::operator=(const vecto &a)

{

num= a.num;

delete [] p;

p= new int [num];

assert(p!=0);

for( int i=0 ; i<num; i++) p[i] = a.p[i];

return *this;

}

istream &operator>>( istream &in, vecto &a)

{

cout<<"Nhap so phan tu:"<<endl;

in>>a.num;

cout<<"Nhap cac gia tri cho cac phan tu: "<<endl;

for ( int i=0; i<a.num; i++) {

cout<<"a.p["<<i<<"]: "<<endl;

in>> a.p[i];

}

return in;

}

ostream &operator <<(ostream &out, const vecto &a)

{

for ( int i=0; i<a.num; i++)

out <<"\t"<<a.p[i];

return out;

}

int & vecto::operator []( int n )

{

assert ( n>=0 && n< num);

return p[n];

}

int main ()

{

vecto vt1,vt2,vt3;

cout<< "Vecto 1: " <<endl;

cin >> vt1;

cout <<"vecto 1:" <<vt1 <<endl;

cout<<" Vecto 2: " <<endl;

cin >>vt2;// >>

cout <<"vecto 2: "<<vt2 <<endl<<endl; // xuat

vt3=vt1+vt2;// phep cong

cout <<"vecto 1:" <<vt1 <<endl;

cout <<"vecto 2: "<<vt2 <<endl;

cout <<"vt3=vt1 + vt2:"<< vt3<<endl;

vt3=vt1-vt2;// phep tru

cout <<"vt3=vt1 - vt2:"<<vt3 <<endl;

vt3=vt1*5; // phep nhan

cout << "vt3=vt1 * (int):"<<vt3<<endl;

int n=vt1.get_num();

vt1[n-1]=-1; // toan tu truy cap

cout <<"vt1: "<<vt1<<endl;

getch();

return 0;

}