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program int; 
uses crt, Math, Graph, wincrt; 
const menuitems: array [1..6] of string =( 
'Info', 
'Enter borders', 
'Enter step', 
'Square and Inaccuracy', 
'Graph', 
'Exit'); 
 
function Funct(x:real):real; 
begin 
Funct:= x*x*x + 2*x*x + x + 7; 
end; 
 
function Pervo(x:real):real; 
begin 
Pervo:= 1/4*x*x*x*x + 2/3*x*x*x + 1/2*x*x +7*x; 
end; 
 
var a, b, s, h, h1, s1, n, x, f, pog: real; 
var UN, i: integer; 
var C1, C2: boolean; 
var h2: longint; 
var Key: char; 
var Gd, Gm: smallint; 
 
procedure vvodgr; 
begin 
writeln ('Write left border, a= '); 
readln (a); 
writeln ('Write right border, b= '); 
readln (b); 
if a <-2.631 then begin 
writeln ('a>-2.630'); 
writeln ('Write left border, a= '); 
readln (a); 
writeln ('Write right border, b= '); 
readln (b); 
end; 
if b<a then begin 
writeln ('Borders are not correct'); 
writeln ('Write left border, a= '); readln (a); 
writeln ('Write right border, b= '); readln (b); 
end; 
writeln ('(Press enter to exit the menu)'); 
C1:= true; 
readln (); 
end; 
 
procedure step1; 
begin 
writeln ('Write a step'); 
readln (n); 
h1:= (b-a); 
if (n<0) or (n>h1) then begin 
writeln ('Incorrect step. Please try again'); 
readln; 
end; 
if (n>0) and (n<=h1) then 
writeln ('(Press enter to exit the menu)'); 
readln; 
C2:=true; 
end; 
 
procedure menu (UN: integer); 
var Item: integer; 
begin 
for Item:= 1 to length (menuitems) do begin 
if Item = UN then 
TextBackground (LightRed) 
else TextBackground (Black); 
Writeln (Item, '.', menuitems[Item]); 
TextBackground (Black); 
end; 
 
end; 
 
procedure sqin; 
begin 
s:=0; 
x:=a; 
h:=(b-a)/n; 
h2:= Round (h); 
f:=0; 
for i:=0 to h2-1 do 
begin 
x:= a+h2*n; 
s1:=Funct (x); 
s:=s+s1; 
end; 
s:=s*n; 
Gotoxy (27, 10); 
writeln ('Square is ', s: 0:6); 
begin 
pog:=Pervo(b)-Pervo(a); 
end; 
Gotoxy (25, 12); 
Writeln ('Absolute inaccuracy= ', Abs (pog-s): 5:6); 
GotoXy (25, 13); 
Writeln ('Relative inaccuracy= ', ((Abs (pog-s))/s)*100: 3:6, '%'); 
Gotoxy (25,15); 
writeln ('(Press enter to exit the menu)'); 
end; 
 
procedure graph; 
var x0, y0, x3, y3, xLeft, yLeft, xRight, yRight, n2, colx, coly, jk, y4: integer; 
a1, b1, fmin, fmax, x1, y1, mx, my, dx, dy, num: real; 
l: byte; 
s2: string; 
chaf: char; 
begin 
colx:= 3; 
coly:= 3; 
clrscr; 
Gd:= Detect; 
InitGraph (Gd, Gm, ''); 
a1:= -6; b1:= 6; dx:= 0.5; 
fmin:= -250; fmax:= 250; dy:= 50; 
repeat 
jk:=0; 
x0:= 0; 
xLeft:= 25; 
yLeft:= 25; 
xRight:= GetMaxX - 50; 
yRight:= GetMaxY - 50; 
mx:= (xRight - xLeft)/(b1-a1); 
my:= (yRight - yLeft)/(fmax-fmin); 
x0:= trunc (abs(a1)*mx) + xLeft; 
y0:= yRight - trunc (abs(fmin)*my); 
Setcolor (15); 
line (xLeft, y0, xRight, y0); 
line (x0, yLeft, x0, yRight); 
Setcolor (4); 
SetTextStyle(1, 0, 1); 
OutTextXY (xRight+20, y0 - 15, 'X'); 
OutTextXY (x0 - 15, yLeft - 10, 'Y'); 
Setcolor (14); 
OutTextXY (x0 - 10, y0 + 10, '0'); 
x1:=a1; 
while x1 <= b1 do 
begin 
y1:= Funct (x1); 
x3:= x0 + Round (x1 * mx); 
y3:= y0 - Round (y1 * my); 
y4:=y3; 
if (x1>=a) and (x1<=b) and (x3<>x0) then 
begin 
Setcolor (2); 
if y4<yLeft then y4:=yLeft; 
line (x3, y4, x3, y0 - 2); 
end; 
if (y3 >= yLeft) and (y3 <= yRight) then PutPixel (x3, y3, 12); 
x1:= x1 + 0.0001; 
end; 
Setcolor (14); 
n2:= Round ((b1-a1)/dx) + 1; 
for l:= 1 to n2 do 
begin 
num:= a + (l-1) * dx; 
x3:= xLeft + trunc (mx* (num-a)); 
Line (x3, y0 - 3, x3, y0 + 3); 
str(Num:0:1, s2); 
if abs(num) > 1E-15 then 
OutTextXY (x3 - TextWidth(s2) div 2, y0+ 10, s2) 
end; 
n2:= Round ((fmax - fmin)/dy) + 1; 
for l:= 1 to n2 do 
begin 
num:= fMin + (l-1) * dy; 
y3:= yRight - trunc (my * (num - fmin)); 
Line (x0 - 3, y3, x0 + 3, y3); 
str (num:0:0, s2); 
if abs (num) > 1E-15 then 
OutTextXY (x0 + 7, y3 - TextHeight (s2) div 2, s2) 
end; 
Setcolor (2); 
OutTextXY (400, 10, 'F(x)= x^3+2x^2+x+7'); 
OutTextXY (0, 20, 'Zoom in X and Y - "Up arrow"'); 
OutTextXY (0, 32, 'Reduce X and Y - "Down arrow"'); 
OutTextXY (0, 44, 'Zoom in X - "Insert"'); 
OutTextXY (0,56,
 
'Reduce X - "PGUP"'); 
OutTextXY (0, 68, 'Zoom in Y - "Delete"'); 
OutTextXY (0, 80, 'Reduce Y - "PGDN"'); 
OutTextXY (0,92, 'Exit - "Esc"'); 
chaf:= wincrt.readkey; 
if chaf=#0 then chaf:= wincrt.readkey; 
case chaf of 
#82: begin 
if (colx<6) then 
begin 
a1:= a1 * 2; b1:= b1 * 2; dx:= dx*2; 
colx:= colx+1; 
cleardevice 
end 
else 
begin 
OutTextXY (0, 106, 'Error - X max limit'); 
delay (600); 
cleardevice; 
end; 
end; 
#73: begin 
if (colx>1) then 
begin 
a1:= a1/2; b1:= b1/2; dx:= dx/2; 
colx:=colx-1; 
cleardevice; 
end 
else 
begin 
OutTextXY (0, 106, 'Error - X min limit'); 
delay (600); 
cleardevice; 
end; 
end; 
#83: begin 
if (coly<6) then 
begin 
fmin:=fmin*2; fmax:=fmax*2; dy:= dy*2; 
coly:=coly+1; 
cleardevice; 
end 
else 
begin 
OutTextXY (0, 106, 'Error - Y max limit'); 
delay (600); 
cleardevice; 
end; 
end; 
#81: begin 
if (coly>1) then 
begin 
fmin:=fmin/2; fmax:=fmax/2; dy:=dy/2; 
coly:=coly-1; 
cleardevice 
end 
else 
begin 
OutTextXY (0, 106, 'Error - Y min limit'); 
delay (600); 
cleardevice; 
end; 
end; 
#75: begin 
if (colx<6) then 
begin 
a1:= a1*2; b1:= b1*2; dx:= dx*2; 
colx:=colx+1; 
cleardevice 
end 
else 
begin 
OutTextXY (0, 106, 'Error - X max limit'); 
delay (600); 
cleardevice; 
end; 
if (coly<6) then 
begin 
fmin:=fmin*2; fmax:=fmax*2; dy:= dy*2; 
coly:= coly+1; 
end 
else 
begin 
OutTextXY (0, 118, 'Error - Y max limit'); 
delay (600); 
cleardevice; 
end; 
end; 
#77: begin 
if (colx>1) then 
begin 
a1:= a1/2; b1:= b1/2; dx:= dx/2; 
colx:= colx-1; 
end 
else 
begin 
OutTextXY (0, 106, 'Error - X min limit'); 
delay (600); 
end; 
if (coly>1) then 
begin 
fmin:=fmin/2; fmax:=fmax/2; dy:= dy/2; 
coly:=coly-1; 
end 
else 
begin 
OutTextXY (0, 118, 'Error - Y min limit'); 
delay (600); 
cleardevice; 
end; 
cleardevice; 
end; 
end; 
until chaf=#27; 
closeGraph; 
end; 
 
 
begin 
C1:= false; 
C2:= false; 
UN:= 1; 
while true do begin 
clrscr (); 
menu (UN); 
while true do begin 
Key:= ReadKey (); 
if Key = #13 then break; 
if Key <> char (0) then continue; 
Key:= ReadKey(); 
case Key of 
#72: UN:= UN - 1; 
#80: UN:= UN + 1; 
end; 
if UN > length (menuitems) then UN:=1 
else if UN <1 then UN:= length (menuitems); 
clrscr(); 
menu (UN); 
end; 
clrscr (); 
menu (0); 
Writeln (); 
case UN of 
1: begin 
Gotoxy (32, 7); 
writeln ('f(x)= x^3+2x^2+x+7'); 
Gotoxy (31,8); 
writeln ('Left rectangle method'); 
Gotoxy (29, 10); 
writeln ('(Press enter to continue)'); 
readln (); 
end; 
2: vvodgr; 
3: step1; 
4: begin 
if ((C1=false) or (C2=false)) then begin 
writeln ('Enter all data'); 
end 
else begin 
sqin; 
end; 
readln (); 
end; 
5: graph; 
6: exit; 
end;