/* File: factorial.chimera
 * Computes factorials using iteration and recursion.
 * (C) 2019 Ariel Ortiz, ITESM CEM
 */

var
    option: string;
    num: integer;

procedure IterativeFactorial(
        n: integer;
    ): integer;

    var
        i, r: integer;

    begin
        r := 1;
        i := 2;

        loop
            if i > n then exit; end;
            r := r * i;
            i := i + 1;
        end;

        return r;
    end;

procedure RecursiveFactorial(
        n: integer;
    ):integer;

    begin
        if n <= 1 then
            return 1;
        else
            return n * RecursiveFactorial(n - 1);
        end;
    end;

program
    loop
        WrStr("Input a number: ");
        num := RdInt();

        WrStr("Iterative factorial: ");
        WrInt(IterativeFactorial(num));

        WrLn();

        WrStr("Recursive factorial: ");
        WrInt(RecursiveFactorial(num));

        WrLn();

        WrStr("Compute another factorial? ");
        option := RdStr();

        if LenStr(option) = 0 then
            option := "N";
        else
            option := AtStr(option, 0);
        end;

        if CmpStr(option, "Y") <> 0 and CmpStr(option, "y") <> 0 then
            exit;
        end;
    end;
end;