Код:
//Dev-Pascal 1.9.2
//P,S
program Pabc_Sabc;
uses crt;

var
a,b,c : real;
P,S : real;

begin
ClrScr;

write('Vuvedete strana a :');readln(a);
write('Vuvedete strana b :');readln(b);
write('Vuvedete strana c :');readln(c);

if ((a>0) and (b > 0) and (c>0)) then
begin
P := a+b+c;
S := a*b/2;
writeln('P = ', P);
writeln('S = ', S);
end
else
begin
writeln('Ne moje da napravim triugulnik s tezi strani !');
end

end.
Ето ти и кода за програмата.