Построение Блок-схемы

uses graphABC;
function F(x:real):real;
begin
F:=sqrt(1-x*x);
end;
var xn,xk,x,h,ymx,m:real;
    x1,y1:array[1..30] of real;
    n,i,x0,y0,y:integer;
    st:string;
begin
xn:=-1;
xk:=1;
h:=0.1;
 
ymx:=F(xn);
x:=xn;
n:=0;
while x<=xk do
 begin
  n:=n+1;
  x1[n]:=x;
  y1[n]:=F(x1[n]);
  if y1[n]>ymx then ymx:=y1[n];
  x:=x+h;
 end;
 setwindowsize(640,500);
 
x0:=2*windowwidth div 3-50;
y0:=windowheight-170;
 
m:=(windowwidth-x0-10)/xk;
 
line(x0-round(xk*m),y0,x0+round(xk*m),y0);
textout(windowwidth-25,y0-15,'X');
line(x0,y0,x0,60);
textout(x0+10,60,'Y');
for i:=0 to 10*trunc(xk) do
 begin
  line(x0+round(m*i/10),y0+3,x0+round(m*i/10),y0-3);
  line(x0-round(m*i/10),y0+3,x0-round(m*i/10),y0-3);
  str(i*0.1:0:1,st);
  if i mod 2=0 then
   begin
    textout(x0+round(m*i/10),y0+10,st);
    textout(x0-round(m*i/10),y0+10,'-'+st);
   end;
  line(x0+3,y0-round(m*i/10),x0-3,y0-round(m*i/10));
  textout(x0-30,y0-round(m*i/10),st);
 end;
 
y:=round(m*y1[1]);
moveto(x0+round(x1[1]*m),y0+y-round(y1[1]*m));
setpencolor(clGreen);
circle(x0+round(x1[1]*m),y0+y-round(y1[1]*m),2);
for i:=1 to n do
 begin
  setpencolor(clRed);
  lineto(x0+round(x1[i]*m),y0+y-round(y1[i]*m));
  setpencolor(clGreen);
  circle(x0+round(x1[i]*m),y0+y-round(y1[i]*m),2);
  x:=x+h;
 end;
setpencolor(clRed);
textout(x0-60,0,'Функція y=sqrt(1-sqr(x))');
textout(x0-50,20,'на проміжку [-1;1]');
 
setpencolor(clBlack);
textout(10,0,'');
textout(30,20,'Таблиця значень функції');
line(10,50,10,50+(n+1)*18);
line(60,50,60,50+(n+1)*18);
line(110,50,110,50+(n+1)*18);
for i:=0 to n+1 do
line(10,50+i*18,110,50+i*18);
textout(35,55,'X');
textout(85,55,'Y');
for i:=1 to n do
 begin
  str(x1[i]:0:2,st);
  textout(15,55+18*i,st);
  str(y1[i]:0:2,st);
  textout(65,55+18*i,st);
 end;
end.