Day 23 - C++ Classes

CLASSWORK:
XY Coordinate Class:
// These statements define a class for xy-coordinates.
// This declaration is stored in xy_coordinate.h.
#include <iostream>
#include <cmath>
using namespace std;
class xy_coordinate
{
// Declare function prototypes for public members.
public:
void input();
void print();
double radius();
double angle();
private:
// Declare private data members.
double x, y;
};

// These statements define implementation of an 
// xy_coordinate class. They are stored in xy-coordinate.h.
// This function reads the xy coordinates from the keyboard.
void xy_coordinate::input()
{
cin >> x >> y;
}
// This function prints the xy coordinates to the screen.
void xy_coordinate::print()
{
cout << "(" << x << "," << y << ")" << "\n";
}
// This function computes the radius.
double xy_coordinate::radius()
{
return sqrt(x*x + y*y);
}
// This function computes the angle in radians.
double xy_coordinate::angle()
{
// Compute angle of polar form.
double z, pi=3.141593;
if (x >= 0)
z = atan(y/x);
if (x<0 && y>0)
z = atan(y/x) + pi;
if (x<0 && y<=0)
z = atan(y/x) - pi;
if (x==0 && y==0)
z = 0;
return z;
}