program DIEN_TICH_HINH_TAM_GIAC;
Uses crt;
var a, b, c: integer;
var p, s: real;
begin
CLRSCR;
write ('nhap a: ');
readln (a);
write ('nhap b: ');
readln (b);
write ('nhap c: ');
readln (c);
p:=0;
s:=0;
if (a+b > c) and (b+c > a) and (a+c > b) then
  begin
    p:=(a+b+c)/2;
    s:=sqrt(p*(p-a)*(p-b)*(p-c));
    textcolor (YELLOW);
    writeln ('dien tich cua tam giac la: ',s);
    delay (500);
    textcolor (lightblue);
    writeln ('===============THE END===============');
  readln;
 end
Else
 begin
    textcolor (lightred);
    writeln ('BA CANH NAY KHONG THE TAO THANH 1 TAM GIAC');
    DELAY (1000);
    textcolor (green+blink);
    WRITELN ('MOI BAN CHAY LAI CHUONG TRINH !!!');
  READLN;
 end;
END.

PROGRAM Ten_Chuong_Trinh; ® (*Tieu đe*)
USES ... ® (*Phan khai bao: don vi chuong trinh
LABEL ... nhan ...
CONST ... hang ...
TYPE ... kieu ...
VAR ... bien ...*)
PROCEDURE ... ® (*Phan mo ta thu tuc/ch. trinh con
FUNCTION ... ham ...*).
BEGIN ® (*Than chuong trinh*)
... (*Cac cau lenh chuong trinh*)
END. ® (*Ket thuc chuong trinh*)