/// <summary>
/// Demo of this program. Only for developers seeing this code.
/// </summary>
static void Demo()
{
// if Euler's number e=2.71828... can be approximated by fractions like X1/2, X2/3, ... , X98/99,
// where X1, ... ,X98 are integers, which one will be closest to e?
// Let's check it.
var fs = DecimalToFraction.ConvertDecimalToFraction(Math.E, 2, 99);
Console.WriteLine("*** Euler's number e = {0}", Math.E);
Console.WriteLine("[In order of denominator]");
Console.WriteLine("---------------------------------------------------");
foreach (var f in fs)
{
Console.WriteLine(f.ToString());
}
Console.WriteLine("");
Console.WriteLine("");
Console.WriteLine("[The closest fraction]");
Console.WriteLine(DecimalToFraction.GetClosestFraction(fs).ToString());
Console.WriteLine("");
Console.WriteLine("");
Console.WriteLine("[In order of the absolute value of error]");
Console.WriteLine("---------------------------------------------------");
foreach (var f in fs.OrderBy(f => Math.Abs(f.Error)))
{
Console.WriteLine(f.ToString());
}
}
/// <summary>
/// Reduce a fraction (e.g. 21/9 to 7/3)
/// </summary>
/// <param name="f"></param>
/// <returns></returns>
private DecimalToFraction ReduceFraction(DecimalToFraction f)
{
int gcd = Gcd(f.Denominator, f.Numerator);
if (gcd == 1)
{
return(f);
}
f.Numerator /= gcd;
f.Denominator /= gcd;
return(f);
}
/// <summary>
/// Get the closest fraction to a given decimal number whose denominator is in the given range
/// </summary>
/// <param name="decim">a decimal number</param>
/// <param name="denomRangeMin">the min of the range</param>
/// <param name="denomRangeMax">the max of the range</param>
/// <returns>The closest fraction to a given decimal number</returns>
static public DecimalToFraction GetClosestFraction(double decim, int denomRangeMin, int denomRangeMax)
{
var fs = DecimalToFraction.ConvertDecimalToFraction(decim, denomRangeMin, denomRangeMax);
return(DecimalToFraction.GetClosestFraction(fs));
}
static void Main(string[] args)
{
//foreach (var a in args) Console.WriteLine("{0}", a);
double d = 0;
int min = 0;
int max = 0;
if (!AreArgsValid(args))
{
Console.WriteLine("The parameters are invalid.");
Console.WriteLine("");
while (true)
{
Console.WriteLine("Input a decimal number and minimum and maximum denominators");
Console.WriteLine("For example, if you want to approximate 3.1415 with denominators from 2 to 99, input '3.1415 2 99'");
Console.WriteLine("If you want to quit, just type 'q'");
string s = Console.ReadLine();
if (s == "q")
{
return;
}
args = s.Split(' ');
if (AreArgsValid(args))
{
break;
}
Console.WriteLine("The parameters are invalid.");
Console.WriteLine("");
}
}
d = double.Parse(args[0]);
min = int.Parse(args[1]);
max = int.Parse(args[2]);
var fs = DecimalToFraction.ConvertDecimalToFraction(d, min, max);
Console.WriteLine("[approximated fractions of {0}]", d);
Console.WriteLine("(In order of denominator)");
Console.WriteLine("---------------------------------------------------");
foreach (var f in fs)
{
Console.WriteLine($"{f.Numerator}/{f.Denominator}\t(error : {(f.Error*100).ToString("G3")}%)");
}
Console.WriteLine("");
Console.WriteLine("[The closest fraction]");
var closest = DecimalToFraction.GetClosestFraction(fs);
if (closest != null)
{
Console.WriteLine($"{closest.Numerator}/{closest.Denominator}\t(error : {(closest.Error * 100).ToString("G3")}%)");
}
else
{
Console.WriteLine("none");
}
Console.WriteLine("");
Console.WriteLine("Press any key to exit...");
Console.ReadLine();
return;
}
