Class confusion with ball animation

[ChucklesDarling]

I'm trying to create a class for my simple point animation. I want the user to be able to input a speed for the ball to go and I want the speed to be restricted to between 0.01 and 1.0. I want them to be able to input two velocities: one for xvel and for yvel. Is this possible? I've only included the main parts of the code and also part of the class, but im not sure if its correct. Any help will be greatful! Thank you.

#include "stdafx.h"

//Point Position
float xpos = 0;
float ypos = 0;

//Point Velocity
float xvel = 0.025;
float yvel = 0.02;

//Class
class cAnimation
{
public:
	void setSpeed(x float,y float);
private:
	float speed;  //values between 0.01 and 1.0
};

// renderScene() - render the scene

void drawScene()
{
	// clear the back buffer
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	
	//Create Point
	glPointSize(20);
	glBegin(GL_POINTS);
	//Point Colour
	glColor3f( 1.0f, 1.0f, 1.0f );
	glVertex2f( xpos, ypos );

		//Point Bounce (x,y axis)
		xpos = xpos + xvel;
		ypos = ypos + yvel;

		if(xpos >= 500)
		{
			xvel = -xvel;
		}
		if(xpos <= -500)
		{
			xvel = -xvel;
		}
		if(ypos >= 500)
		{
			yvel = -yvel;
		}
		if(ypos <= -500)
		{
			yvel = -yvel;
		}

	glEnd();
	
	// swap the buffers of the current window
	glutSwapBuffers();
}


// _tmain() - program entry point

int _tmain(int argc, _TCHAR* argv[])
{	
	// initialise the glut library
	glutInit(&argc, argv);

	// set up the initial display mode
	// need both double buffering and z-buffering
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);

	// set the initial window position
	glutInitWindowPosition(100, 100);

	// set the initial window size
	glutInitWindowSize(500, 500);

	// create and name the window
	glutCreateWindow("Motion Blur Swipe Trails!");

	// reshape callback for current window
	glutReshapeFunc(winReshapeFunc);

	// set display callback for current window
	glutDisplayFunc(drawScene);	

	// set up the global idle callback
	glutIdleFunc(update);

	// enter the glut event processing loop
	glutMainLoop();	

	return 0;
}