Files
CutList/CutToLength/Fraction.cs
2019-11-20 08:22:54 -05:00

86 lines
2.4 KiB
C#

using System;
using System.Text.RegularExpressions;
using System.Text;
using System.Linq;
namespace CutToLength
{
public static class Fraction
{
public static readonly Regex FractionRegex = new Regex(@"((?<WholeNum>\d+)(\ |-))?(?<Fraction>\d+\/\d+)");
public static bool IsValid(string s)
{
return FractionRegex.IsMatch(s);
}
public static double Parse(string s)
{
var match = FractionRegex.Match(s);
if (!match.Success)
throw new Exception("Invalid format.");
var value = 0.0;
var wholeNumGroup = match.Groups["WholeNum"];
var fractionGroup = match.Groups["Fraction"];
if (wholeNumGroup.Success)
{
value = double.Parse(wholeNumGroup.Value);
}
if (fractionGroup.Success)
{
var parts = fractionGroup.Value.Split('/');
var numerator = double.Parse(parts[0]);
var denominator = double.Parse(parts[1]);
value += Math.Round(numerator / denominator, 8);
}
return value;
}
public static string ReplaceFractionsWithDecimals(string input)
{
var sb = new StringBuilder(input);
// find all matches and sort by descending index number to avoid
// changing all previous index numbers when the fraction is replaced
// with the decimal equivalent.
var fractionMatches = FractionRegex.Matches(sb.ToString())
.Cast<Match>()
.OrderByDescending(m => m.Index);
foreach (var fractionMatch in fractionMatches)
{
// convert the fraction to a decimal value
var decimalValue = Parse(fractionMatch.Value);
// remove the fraction and insert the decimal value in its place.
sb.Remove(fractionMatch.Index, fractionMatch.Length);
sb.Insert(fractionMatch.Index, decimalValue);
}
return sb.ToString();
}
public static bool TryParse(string s, out double fraction)
{
try
{
fraction = Parse(s);
}
catch
{
fraction = 0;
return false;
}
return true;
}
}
}