overloading in C++ with vectors

[Sean_8]

Problem1:

Write the definition for a class named Vector2D that stores information about a two-dimensional vector. The class should have methods to get and set the x component and the y component, where x and y are integers.

Next, overload the * operator so that it returns the dot product of two vectors. The dot product of two-dimensional vectors A and B is equal to

`(Ax * Bx) + (Ay * By)`

Next, overload the << and >> operators so that you can write the following code



Vector2D v;

cin >> v;

cout << v;



Finally, write a main program that tests the three overloaded operators.

Sample output (bolded text denote input from user)



(10,0) * (0,10) = 0

(0,10) * (10,10) = 100

(10,10) * (5,4) = 90

You may use the following main() function:

int main()

{

Vector2D v1, v2, v3, v4;

cin>>v1>>v2>>v3>>v4;

cout << v1 <<" * "<< v2<< " = " << v1*v2 << endl;

cout << v2 <<" * "<< v3<< " = " << v2*v3 << endl;

cout << v3 <<" * "<< v4<< " = " << v3*v4 << endl;

return 0;



}

WHAT I HAVE SO FAR:

    # include <iostream>
    # include <vector>
    # include<cmath>


class Vector2D
{
    public:
            Vector2D(void);
            Vector2D(double nx, double ny);
            Vector2D(bool v);
            void normalize(void);
            double magnitude(void);
            void full_dump(void) const;
            bool valid;
            double x,y;

};

double dot(Vector2D v, Vector2D w);

Vector2D operator+(Vector2D v, Vector2D w);

Vector2D operator*(Vector2D v, Vector2D w);

Vector2D operator*(Vector2D v, double w);

Vector2D operator*(double w, Vector2D v);

inline Vector2D::Vector2D(void)
{
    x=y=0;
    valid=true;
}

inline Vector2D::Vector2D(double nx, double ny)
{
    x=nx;
    y=ny;
    valid=true;
}

inline Vector2D::Vector2D(bool v)
{
    x=y=0;
    valid=v;
}

inline Vector2D operator+(Vector2D v, Vector2D w)
{
    return Vector2D(v.x + w.x, v.y + w.y);
}

inline Vector2D operator*(Vector2D v, Vector2D w)
{
    return Vector2D(v.x * w.x, v.y * w.y);
}

inline Vector2D operator*(Vector2D v, double w)
{
    return Vector2D(v.x * w, v.y * w);
}

inline Vector2D operator*(double w, Vector2D v)
{
    return v*w;
}

inline Vector2D operator/(Vector2D v, Vector2D w)
{
    return Vector2D (v.x / w.x, v.y / w.y);
}

inline Vector2D operator/(Vector2D v, double w)
{
    return Vector2D (v.x / w, v.y / w);
}

inline Vector2D operator/(double w, Vector2D v)
{
    return Vector2D (w / v.x, w / v.y);
}

inline void Vector2D::normalize(void)
{
    double mag=magnitude();
    x/=mag;
    y/=mag;
}

inline double Vector2D::magnitude(void)
{
    return sqrt(x*x+y*y);
}

inline Vector2D cross(Vector2D v, Vector2D w)
{
    return Vector2D(0,0);
}

inline double dot(Vector2D v, Vector2D w)
{
    Vector2D x=w*v;
    return x.x + x.y;
}
int main()

{

Vector2D v1, v2, v3, v4;

cin>>v1>>v2>>v3>>v4;

cout << v1 <<" * "<< v2<< " = " << v1*v2 << endl;

cout << v2 <<" * "<< v3<< " = " << v2*v3 << endl;

cout << v3 <<" * "<< v4<< " = " << v3*v4 << endl;

return 0;

}

obviously what I have for the main function wont work, I need help fixing it so that the output will be the same as the example given because im not sure how to overload it. any help is much appreciated! thanks!

[Banfa]

For the main to work you would have to change the output lines to

cout << v1 <<" * "<< v2<< " = " << dot(v1, v2) << endl;

All of your methods pass by value, Vector2D does not contain 2 much data, 2 doubles and a bool so about 20 bytes but I would say it is beginning to get to the point where passing in const references would not hurt

double dot(Vector2D v, Vector2D w);

becomes

double dot(const Vector2D& v, const Vector2D& w);

with the way you have already implemented operator*

Vector2D operator*(Vector2D v, Vector2D w);

there is no way for you to overload the operator so that it produces a dot product because your method dot and operator* have the same parameter list. I suspect you were not supposed to implement operator* as a multiplication in the first place.