Функции и Процедуры!

var
xa1,ya1,xb1,yb1,xc1,yc1,xa2,ya2,xb2,yb2,xc2,yc2,s1,s2:real;
procedure s(xa,ya,xb,yb,xc,yc:real; var stre:real);
var
a,b,c,p:real;
begin
a:=sqrt(sqr(xa-xb)+sqr(ya-yb));
b:=sqrt(sqr(xb-xc)+sqr(yb-yc));
c:=sqrt(sqr(xc-xa)+sqr(yc-ya));
p:=(a+b+c)/2;
stre:=sqrt(p*(p-a)*(p-b)*(p-c));
end;
begin
repeat
writeln('vvedite koordinati 1-go treygolnika');
writeln('xa1,ya1,xb1,yb1,xc1,yc1');
read(xa1,ya1,xb1,yb1,xc1,yc1);
s(xa1,ya1,xb1,yb1,xc1,yc1,s1);
if (s1=0) then writeln('vi vveli priamyiy, a nada treugolnik, poprobyite snova');
until s1<>0;
repeat
writeln('vvedite koordinati 2-go treygolnika');
writeln('xa2,ya2,xb2,yb2,xc2,yc2');
read(xa2,ya2,xb2,yb2,xc2,yc2);
s(xa2,ya2,xb2,yb2,xc1,yc2,s2);
if (s2=0) then writeln('vi vveli priamyiy, a nada treugolnik, poprobyite snova');
until s2<>0;
writeln('plochad 1-go treygolnika=',s1:5:2);
writeln('plochad 2-go treygolnika=',s2:5:2);
if s1<s2 then writeln('2-oi treygolnik bolshe 1-go')
         else begin if s1=s2 then writeln('treygolniki ravni')
                             else writeln('1-i treygolnik bolshe 2-go');
              end;
writeln;
end.