min:
function min(a,b,c: real): real;
begin
if (a<=b) and (a<=c) then min:=a;
if (b<=a) and (b<=c) then min:=b;
if (c<=b) and (c<=a) then min:=c;
end;
max:
function max(a,b,c: real): real;
begin
if (a>=b) and (a>=c) then max:=a;
if (b>=a) and (b>=c) then max:=b;
if (c>=b) and (c>=a) then max:=c;
end;