$ include "seed7_05.s7i";

const func integer: fib (in integer: x) is func
  result
    var integer: fib is 0;
  local
    const func integer: fib1 (in integer: n) is func
      result
        var integer: fib1 is 0;
      begin
        if n < 2 then
          fib1 := n;
        else
          fib1 := fib1(n-2) + fib1(n-1);
        end if;
      end func;
  begin
    if x < 0 then
      raise RANGE_ERROR;
    else
      fib := fib1(x);
    end if;
  end func;

const proc: main is func
  local
    var integer: i is 0;
  begin
    for i range 0 to 4 do
      writeln(fib(i));
    end for;
  end func;