firational.cs

对gif

				numerator = continuedFraction[i] * numerator + denominator;
				denominator = temp;
			}
		}

		/// <summary>
		/// Tries 'brute force' to approximate <paramref name="value"/> with a fraction.
		/// </summary>
		private static void ApproximateFraction(decimal value, int maxDen, out int num, out int den)
		{
			num = 0;
			den = 0;
			decimal bestDifference = 1m;
			decimal currentDifference = -1m;
			int digits = GetDigits(value);

			if (digits <= 9)
			{
				int mul = 1;
				for (int i = 1; i <= digits; i++)
				{
					mul *= 10;
				}
				if (mul <= maxDen)
				{
					num = (int)(value * mul);
					den = mul;
					return;
				}
			}

			for (int i = 1; i <= maxDen; i++)
			{
				int numerator = (int)Math.Floor(value * (decimal)i + 0.5m);
				currentDifference = Math.Abs(value - (decimal)numerator / (decimal)i);
				if (currentDifference < bestDifference)
				{
					num = numerator;
					den = i;
					bestDifference = currentDifference;
				}
			}
		}

		/// <summary>
		/// Converts the numeric value of the <see cref="FIRational"/> object
		/// to its equivalent string representation.
		/// </summary>
		/// <returns>The string representation of the value of this instance.</returns>
		public override string ToString()
		{
			return ((IConvertible)this).ToDouble(null).ToString();
		}

		/// <summary>
		/// Tests whether the specified object is a <see cref="FIRational"/> structure
		/// and is equivalent to this <see cref="FIRational"/> structure.
		/// </summary>
		/// <param name="obj">The object to test.</param>
		/// <returns><b>true</b> if <paramref name="obj"/> is a <see cref="FIRational"/> structure
		/// equivalent to this <see cref="FIRational"/> structure; otherwise, <b>false</b>.</returns>
		public override bool Equals(object obj)
		{
			return ((obj is FIRational) && (this == ((FIRational)obj)));
		}

		/// <summary>
		/// Returns a hash code for this <see cref="FIRational"/> structure.
		/// </summary>
		/// <returns>An integer value that specifies the hash code for this <see cref="FIRational"/>.</returns>
		public override int GetHashCode()
		{
			return base.GetHashCode();
		}

		#region Operators

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator +(FIRational r1)
		{
			return r1;
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator -(FIRational r1)
		{
			r1.numerator *= -1;
			return r1;
		}

		/// <summary>
		/// Returns the reciprocal value of this instance.
		/// </summary>
		public static FIRational operator ~(FIRational r1)
		{
			int temp = r1.denominator;
			r1.denominator = r1.numerator;
			r1.numerator = temp;
			r1.Normalize();
			return r1;
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator ++(FIRational r1)
		{
			checked
			{
				r1.numerator += r1.denominator;
			}
			return r1;
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator --(FIRational r1)
		{
			checked
			{
				r1.numerator -= r1.denominator;
			}
			return r1;
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator +(FIRational r1, FIRational r2)
		{
			long numerator = 0;
			long denominator = Scm(r1.denominator, r2.denominator);
			numerator = (r1.numerator * (denominator / r1.denominator)) + (r2.numerator * (denominator / r2.denominator));
			Normalize(ref numerator, ref denominator);
			checked
			{
				return new FIRational((int)numerator, (int)denominator);
			}
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator -(FIRational r1, FIRational r2)
		{
			return r1 + (-r2);
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator *(FIRational r1, FIRational r2)
		{
			long numerator = r1.numerator * r2.numerator;
			long denominator = r1.denominator * r2.denominator;
			Normalize(ref numerator, ref denominator);
			checked
			{
				return new FIRational((int)numerator, (int)denominator);
			}
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator /(FIRational r1, FIRational r2)
		{
			int temp = r2.denominator;
			r2.denominator = r2.numerator;
			r2.numerator = temp;
			return r1 * r2;
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static FIRational operator %(FIRational r1, FIRational r2)
		{
			r2.Normalize();
			if (Math.Abs(r2.numerator) < r2.denominator)
				return new FIRational(0, 0);
			int div = (int)(r1 / r2);
			return r1 - (r2 * div);
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static bool operator ==(FIRational r1, FIRational r2)
		{
			r1.Normalize();
			r2.Normalize();
			return (r1.numerator == r2.numerator) && (r1.denominator == r2.denominator);
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static bool operator !=(FIRational r1, FIRational r2)
		{
			return !(r1 == r2);
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static bool operator >(FIRational r1, FIRational r2)
		{
			long denominator = Scm(r1.denominator, r2.denominator);
			return (r1.numerator * (denominator / r1.denominator)) > (r2.numerator * (denominator / r2.denominator));
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static bool operator <(FIRational r1, FIRational r2)
		{
			long denominator = Scm(r1.denominator, r2.denominator);
			return (r1.numerator * (denominator / r1.denominator)) < (r2.numerator * (denominator / r2.denominator));
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static bool operator >=(FIRational r1, FIRational r2)
		{
			long denominator = Scm(r1.denominator, r2.denominator);
			return (r1.numerator * (denominator / r1.denominator)) >= (r2.numerator * (denominator / r2.denominator));
		}

		/// <summary>
		/// Standard implementation of the operator.
		/// </summary>
		public static bool operator <=(FIRational r1, FIRational r2)
		{
			long denominator = Scm(r1.denominator, r2.denominator);
			return (r1.numerator * (denominator / r1.denominator)) <= (r2.numerator * (denominator / r2.denominator));
		}

		#endregion

		#region Conversions

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="Boolean"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Boolean"/> initialized to <paramref name="value"/>.</returns>
		public static explicit operator bool(FIRational value)
		{
			return (value.numerator != 0);
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="Byte"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Byte"/> initialized to <paramref name="value"/>.</returns>
		public static explicit operator byte(FIRational value)
		{
			return (byte)(double)value;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="Char"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Char"/> initialized to <paramref name="value"/>.</returns>
		public static explicit operator char(FIRational value)
		{
			return (char)(double)value;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="Decimal"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Decimal"/> initialized to <paramref name="value"/>.</returns>
		public static implicit operator decimal(FIRational value)
		{
			return value.denominator == 0 ? 0m : (decimal)value.numerator / (decimal)value.denominator;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="Double"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Double"/> initialized to <paramref name="value"/>.</returns>
		public static implicit operator double(FIRational value)
		{
			return value.denominator == 0 ? 0d : (double)value.numerator / (double)value.denominator;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to an <see cref="Int16"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Int16"/> initialized to <paramref name="value"/>.</returns>
		public static explicit operator short(FIRational value)
		{
			return (short)(double)value;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to an <see cref="Int32"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Int32"/> initialized to <paramref name="value"/>.</returns>
		public static explicit operator int(FIRational value)
		{
			return (int)(double)value;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to an <see cref="Int64"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Int64"/> initialized to <paramref name="value"/>.</returns>
		public static explicit operator long(FIRational value)
		{
			return (byte)(double)value;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="Single"/> structure.
		/// </summary>
		/// <param name="value">A <see cref="FIRational"/> structure.</param>
		/// <returns>A new instance of <see cref="Single"/> initialized to <paramref name="value"/>.</returns>
		public static implicit operator float(FIRational value)
		{
			return value.denominator == 0 ? 0f : (float)value.numerator / (float)value.denominator;
		}

		/// <summary>
		/// Converts the value of a <see cref="FIRational"/> structure to a <see cref="SByte"/> structure.