Bezier curve using OpenGL

Write a C/C++ program to draw a Bezier curve having the control points as p0 (0, 0), P1 (2, 5), P2 (5, 9), P3 (10, 20). Calculate the coordinates of the points on the curve corresponding to the parameter u = 0.2, 0.4, 0.6.

#include <windows.h>
#include <GL/glut.h>
#include <math.h>

// Point class to keep it a little cleaner.
class Point {
public:
    float x, y;
    void setxy(float x2, float y2) { x = x2; y = y2; }
    const Point & operator=(const Point &rPoint) {
         x = rPoint.x;
         y = rPoint.y;        
         return *this;
      }

};

Point abc[4];

void myInit() {
    glClearColor(0.0,0.0,0.0,0.0);
    glColor3f(1.0,0.0,0.0);
    glPointSize(8.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0,64.0,0.0,48.0);
}

void drawDot(int x, int y) {
    glBegin(GL_POINTS);
    glVertex2i(x,y);
    glEnd();
    glFlush();
}

void drawLine(Point p1, Point p2) {
    glBegin(GL_LINES);
    glVertex2f(p1.x, p1.y);
    glVertex2f(p2.x, p2.y);
    glEnd();
    glFlush();
}

// Calculate the next bezier point.
Point drawBezier(Point A, Point B, Point C, Point D, double t) {
    Point P;
    P.x = pow((1 - t), 3) * A.x + 3 * t * pow((1 -t), 2) * B.x + 3 * (1-t) * pow(t, 2)* C.x + pow (t, 3)* D.x;
    P.y = pow((1 - t), 3) * A.y + 3 * t * pow((1 -t), 2) * B.y + 3 * (1-t) * pow(t, 2)* C.y + pow (t, 3)* D.y;      
    return P;
}

void myDisplay() {
    glClear(GL_COLOR_BUFFER_BIT);   
    Point POld=abc[0];
    abc[0].x=0,abc[0].y=0;
    abc[1].x=2,abc[1].y=5;
    abc[2].x=5,abc[2].y=9;
    abc[3].x=10,abc[3].y=20;
    glColor3f(1.0,0.0,0.0);
    for(int i=0;i<4;i++)
        drawDot(abc[i].x, abc[i].y);       
    glColor3f(1.0,1.0,1.0);
    drawLine(abc[0], abc[1]);
    drawLine(abc[1], abc[2]);
    drawLine(abc[2], abc[3]);   
    for(double t = 0.0;t <= 1.0; t += 0.1) {
        Point P = drawBezier(abc[0], abc[1], abc[2], abc[3],  t);
        drawLine(POld, P);
        POld = P;       
    }
    glFlush();
}

int main(int argc, char *argv[]) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(100,150);
    glutCreateWindow("Bezier Curve");   
    glutDisplayFunc(myDisplay);
    myInit();
    glutMainLoop();
    return 0;
}