{
   Programa para o calculo da serie:
   x = 1 - 1/2 + 1/3 - 1/4 + ... + 1/99 - 1/100
}
program serie;
var
   x	: real;
   i, s	: integer;
begin
   x := 0;
   s := 1;
   i := 1;
   while i <= 100 do
   begin
      x := x + s/i;
      s := -s; { inverte o sinal }
      i := i + 1;
   end;
   writeln('x = ', x:2:3);
end.