Expert: Eddie - 10/24/2009

Question
could u pls help mi,i realli need your help.i am trying to do a simple addition of using class vector.i hope u could guide mi.i'm nt sure whether i'm doing it right anot.i will be so appericated for all the help frm u.

example:A vector can be represented in Cartesian coordinates (a, b, c).
Suppose vector X is (a1, b1, c1) and Y is (a2, b2, c2).
Addition:X + Y = (a1+a2, b1+b2, c1+c2).

example result:
Inputs
A(5,6,7)
B(3,8,2)
Outputs A + B (8,14,9)

code:
class myVector
{
  int x,y,z;
   public:
      myVector operator+(const myVector &mv)const;
};

myVector myVector::operator +(const myVector &mv)const  //Addition
{
  myVector mv;
  mv.x = x + mv.x;
  mv.y = y + mv.y;
  mv.z = z + mv.z;
  return mv;
}

//main program to test the class
int main()
{

  myVector A,B,C;
  
  cout << "Enter first vector, format (a,b,c): ";
  cin >> A;
  
  cout << "Enter second vector, format (a,b,c): ";
  cin >> B;
                        
  C = A + B;
  cout<<"Addition A+B = "<< C << endl;

return 0;
}  

Answer
Hello lisa, thank you for the question.

You're actually very close. You want to modify the class on the left side of the operator though. Try this:

void myVector::operator +(const myVector &mv)
{
this->x += mv.x;
this->y += mv.y;
this->z += mv.z;
}

If you want to be able to print the myVector class, you also need to overload the << operator:

ostream& myVector::operator << (const ostream &o) const;
{
o << this->x << endl;
o << this->y << endl;
o << this->z << endl;
return o;
}

That should have you fixed up and ready to go. Let me know if it doesn't work. I haven't overloaded a << operator on a class in a while.

I hope this information was helpful.

- Eddie