Штриховка замкнутой области в системе координат

#include <graphics.h>
#include <stdio.h>
#include <conio.h>
#include <math.h>
#include<cmath>
const int X0= 200, Y0 = 400,
        k= 60;
int ScreenX (float x)
{
    return X0+k*x;
}
int ScreenY (float y)
{
    return Y0-k*y;
}
void Axes()
{
int i, xe, ye;
char s[5];
line (X0, 0, X0, 599);
line (0, Y0, 799, Y0);
for (i=0; i <= (800-X0)/k; i++)
    {
    xe= ScreenX(i);
    line (xe, Y0-2, xe, Y0+2);
    sprintf(s, "%d", i);
    outtextxy(xe-8, Y0+4, s);
    }
for (i=1; i <= (600-X0)/k; i++)
{
ye= ScreenY(i);
line (X0-2, ye, X0+2, ye);
sprintf (s, "%d", i);
outtextxy(X0-10, ye, s);
}
}
//------------------------------------------
void Point (float x, float y, int color)
{
    int xe, ye;
    xe = ScreenX(x);
    ye = ScreenY(y);
    if (xe >= 0 && xe < 800 &&
        ye >= 0 && ye < 600);
      putpixel(xe, ye, color);
}
float f1 (float x)
{
    return 2-x*x;
}
float f2 (float x)
{
    return x;
}
int odz1 (float x)
{
    return (x >= -3);
}
//----------------------------------------
void Plot ()
{
    float xmin = -1.*X0/k,
        xmax = (800. - X0)/k;
    float x,
        h= (xmax - xmin)/1000;
    for (x= xmin; x<= xmax; x+=h)
        if ( odz1(x) )
            Point(x, f1(x), LIGHTRED);
            for (x = xmin; x<= xmax; x+=h)
    Point (x, f2(x), LIGHTRED);
}
//----------------------------------------------
float Solve (float a, float b, float eps)
{
float c, fa, fc;
while(fabs(b-a)>eps) {
    c = (a + b)/ 2.;
    fa = f1(a) - f2(a);
    fc = f1(c) - f2(c);
    if (fa*fc < 0) b = c;
    else            a = c;
    }
return (a + b)/ 2.;
}
//---------------------------------
void Cross ()
{
    float y, x1, x2;
    int xe, ye;
     char s[30];
    x1 = Solve(1., 1., 0.001);
    y = f1(x1);
    xe = ScreenX(x1);
    ye = ScreenY(y);
    sprintf(s, "x1:%5.2f", x1);
    outtextxy(xe+5, ye+2, s);
    sprintf(s, "y:%5.2f", y);
    outtextxy(xe+5, ye+22, s);
    //----------------------------
    x2 = Solve (-2., -2., 0.001);
    y = f1(x2);
    xe = ScreenX(x2);
    ye = ScreenY(y);
    sprintf(s, "x2:%5.2f", x2);
    outtextxy(xe+5, ye+2, s);
    sprintf(s, "y2:%5.2f", y);
    outtextxy(xe+5, ye+22, s);
}
//--------------------------------------
void Hatch()
{
    const int N = 30;
    float x, x2, x1, h = (x2 - x1) / (N + 1);
    int xe, yUp, yDown;
    for (x = x1+h; x <= x2; x += h)
        {
        xe = ScreenX (x);
        yUp = ScreenY (f1(x));
        yDown = ScreenY (f2(x));
        line (xe, yUp, xe, yDown );
        }
//-----------------------------------------------
}
main()
{
    initwindow(800, 600);
    Axes();
    Plot();
    Cross();
    Hatch();
    getch();
    closegraph();
}

float x, x2 = 200, x1 = 100, h = (x2 - x1) / (N + 1);