Небольшая проблема с концом отрезка - прошу помочь

Program pro3;
Uses crt;
var a,b,f,x,h:real;
label M1,M2;
Begin
Clrscr;
Write('nachalo otrezka a=');
Readln(a);
Write('konec otrezka b=');
Readln(b);
Write('vvedite h=');
Readln(h);
writeln('|-----------|');
writeln('| x   | f(x)|');
writeln('|-----------|');
x:=a; M1:
if x>=-2 then
begin
while x<=0 do
   begin
   f:=exp(-x);
  goto M2; end;
  begin
  if x>0 then
 while x<2 do
    begin
 f:=0.5*x+1;
 goto M2; end;
 begin
  if x>=2 then
 while x<=b  do
begin
f:=4-x;
goto M2;
M2:
writeln ('|',x:1:2, ' | ',f:1:2, '|');
writeln('|-----------|');
x:=x+h;
goto M1;
end; end; end; end;
readkey;
 
end.

Uses crt;
var a,b,h:real;
    l:byte;
Begin
Clrscr;
a:=-2;
b:=3;
l:=0;
h:=0.2;
while a<b+h do
begin
 if (a>=-2) and (a<=0) then writeln('-2 <= x <= 0; x:=',a:1:1,' F(x):=',exp(-a):1:3)
 else if (a>0) and (a<2) then writeln('0<x<2; x:=',a:1:1,' F(x):=',0.5*a+1:1:3)
 else writeln('2<=x<=3; x:=',a:1:1,' F(x):=',4-a:1:3);
 inc(l);
 if l mod 20=0 then readln;
 a:=a+h;
end;
readkey;
end.

Program pro_while;
Uses crt;
var a,b,x,h: real;
Begin Clrscr;
Write('nachalo otrezka a='); Read(a);
Write('konec otrezka b=');   Read(b);
Write('vvedite h=');         Read(h);
writeln('|-----------|');
writeln('| x   | f(x)|');
writeln('|-----------|');
x:=a;
while x<b+h do
begin
  if (x<=0)  then
writeln ('|',x:1:2, ' | ',exp(-x):1:2, '|');
  if (x>0) and (x<2) then
writeln ('|',x:1:2, ' | ',0.5*x+1:1:2, '|');
  if (x>=2) and (x<=b+0.000000001) then
writeln ('|',x:1:2, ' | ',4-x:1:2, '|');
x:=x+h; end;
readkey;
end.