program grafik_funkcii;
uses crt, graph;
var {koord gr f-i}
    x,y,a,b:real;
    {N tipa graf drayvera i N graf rejima}
    driver,mode:integer;
    {cx,cy-koord centra sist koord;
    mx,my-mashtab(kol-bo pikseley na ed-cu;
    ex,ey-koord tochek grafika v mashtabe ekrana}
    cx,cy,mx,my,ex,ey,n:integer;
    {opisanie f-i graf}
function f(x:real):real;
         begin
              y:=x*x;
         end;
procedure deleniyaX(a:real);
var
   stroka:string;
   x,s:real;
begin{proceduri}
{delenia vist v 10 tochkah OX ot -a do a s shagom s}
     x:=-a;
     s:=2*a/10;
     repeat
           ex:=trunc(cx+x*mx)-10;
           ey:=cy+5;
           str(x:3:1,stroka);
           outtextxy(ex,ey,stroka);
           x:=x+s;
     until x>a;
end;{proc}
procedure deleniyaY(a:real);
var
   stroka:string;
   y:real; s:integer;
begin{proceduri}
{delenia vist v 10 tochkah OY ot -b do b s shagom s}
          s:=trunc((getmaxy-30)/10);
          ey:=getmaxy-3;
     repeat
           ex:=cx+5;
           y:=b-ey/my;
           str(y:3:1,stroka);
           if abs(y)>0.5 then
           outtextxy(ex,ey+5,stroka);
           ey:=ey-s;
     until ey<10;
end;{proc}
{podprogramma postroenia grafika}
procedure MyGrafik(a,b:real);
{proc stroit grafik ot -a do a c shagom s}
var
   p,n:integer;
   s,t:real;
   strx:string;
begin{proc}
{polojenie nach koord na ekrane}
     cx:=trunc(getmaxx/2);
     cy:=trunc(getmaxy/2);
     {tcvet fona i texta}
     setBkColor(yellow);
     setcolor(blue);
     line(10,cy,getmaxx-50,cy);{os' OX}
     {strelochka na osi OX}
     line(getmaxx-60,cy-5,getmaxx-50,cy);
     line(getmaxx-60,cy+5,getmaxx-50,cy);
     line(cx,10,cx,getmaxy-20);{os' OY}
     {strelochka na osi OY}
     line(cx-5,20,cx,10);
     line(cx+5,20,cx,10);
     setcolor(magenta);
     {podpisi po os'am}
     outtextxy(cx+10,10,'y');
     outtextxy(getmaxx-50,cy-10,'x');
     {opredelenie mashtaba po os'am} {x ot -a do a}
     mx:=trunc((getmaxx)/(2*a));
     {y ot -b do b}
     my:=trunc((getmaxx)/(2*b));
     {vivod znacheniy po osi x ot -a do a}
     deleniyaX(a);
     {po y ot -b do b}
     deleniyaY(b);
     outtextxy(10,50,'grafik funkcii');
     {x meniaetsa ot -a do a s shagom s v n+1 tochke}
     x:=-a;n:=500; s:=2*a/n;
     moveto(trunc(cx+x*mx), trunc(cy-f(x)*my));
     repeat
           y:=f(x);
           ex:=trunc(cx+x*mx);
           ey:=trunc(cy-y*my);
           lineto(ex,ey);
           x:=x+s;
     until ex>getmaxx-70;
end;{proc}
begin{osnovnaya}
clrscr;
writeln('a=');
readln(a);
writeln('b=');
readln(b);
{otkritie graficheskogo rejima}
driver:=detect;
initgraph(driver,mode,'c:\paskal\turbo.exe');
{ochistka ekrana v grficheskom rejime}
cleardevice;
{vipoln proc vivoda grafika}
MyGrafik(a,b);
{zaderjka}
repeat
{do najatiya ENTER}
until keypressed;
end.{osnovnoy}
end.