RoundToSignificantFigures

RoundToSignificantFigure.cs

        public static double RoundToSignificantDigits( double d, int digits )
        {
            var scale = (decimal) Math.Pow(10, Math.Floor(Math.Log10(Math.Abs(d))) + 1);
            return (double)( scale * Math.Round((decimal)d / scale, digits));
        }



        [Fact]
        public void RoundToSignificantDigits()
        {
            WMath.RoundToSignificantDigits(0.0012345m, 2).Should().Be(0.0012m);
            WMath.RoundToSignificantDigits(0.0012645m, 2).Should().Be(0.0013m);
            WMath.RoundToSignificantDigits(0.040000000000000008, 6).Should().Be(0.04);
            WMath.RoundToSignificantDigits(0.040000010000000008, 6).Should().Be(0.04);
            WMath.RoundToSignificantDigits(0.040000100000000008, 6).Should().Be(0.0400001);
            WMath.RoundToSignificantDigits(0.040000110000000008, 6).Should().Be(0.0400001);
        }