C/C++ Source Codes

OVERLOADING OF ,+, OPERATOR WITH PROTOTYPE SAME AS NAME OF CLASS NAME

#include <iostream.h>
#include <math.h>
class vector
{
public:
double x;
double y;
vector (double = 0, double = 0);
vector operator + (vector);
vector operator - (vector);
vector operator - ();
vector operator * (double);
double module();
void set_length (double = 1);
};
vector::vector (double a, double b)
{
x = a;
y = b;
}
vector vector::operator + (vector a)
{
return vector (x + a.x, y + a.y);
}
vector vector::operator - (vector a)
{
return vector (x - a.x, y - a.y);
}
vector vector::operator - ()
{
return vector (-x, -y);
}
vector vector::operator * (double a)
{
return vector (a * x, a * y);
}
double vector::module()
{
return sqrt (x * x + y * y);
}
void vector::set_length (double a)
{
vector &the_vector = *this;
double length = the_vector.module();
x = x / length * a;
y = y / length * a;
}
ostream& operator << (ostream& o, vector a)
{
o << "(" << a.x << ", " << a.y << ")";
return o;
}
void main ()
{
vector c (3, 5);
vector *r; // r is a pointer to a vector.
r = new vector; // new allocates the memory necessary
cout << *r << endl; // to hold a vectors' variable,
// calls the constructor who will
// initialize it to 0, 0. Then finally
// new returns the address of the vector.
r->x = 94;
r->y = 345;
cout << *r << endl;
*r = vector (94, 343);
cout << *r << endl;
*r = *r - c;
r->set_length(3);
cout << *r << endl;
*r = (-c * 3 + -*r * 4) * 5;
cout << *r << endl;
delete (r); // Calls the vector destructor then
// frees the memory.
r = &c; // r points towards vector c
cout << *r << endl;
r = new vector (78, 345); // Creates a new vector.
cout << *r << endl; // The constructor will initialise
// the vector's x and y at 78 and 345
cout << "x component of r : " << r->x << endl;
cout << "x component of r : " << (*r).x << endl;
delete (r);
r = new vector[4]; // creates an array of 4 vectors
r[3] = vector (4, 5);
cout << r[3].module() << endl;
delete (r); // deletes the array
int n = 5;
r = new vector[n]; // Cute !
r[1] = vector (432, 3);
cout << r[1] << endl;
delete (r);
}

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