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Егор Куняген
Проверка страницы Кунягена Егора ВКонтакте (VK)
Число подписчиков: 24
- VK ссылка:id380629510
- Ник:kuniahen_andrec
- День рождения:21.9.1945
- Сейчас проживает в:, Львов
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Актуальный статус
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using System; using System.Globalization; ///
/// A class to allow the conversion of doubles to string representations of /// their exact decimal values. The implementation aims for readability over /// efficiency. /// public class DoubleConverter { ////// Converts the given double to a string representation of its /// exact decimal value. /// /// The double to convert. ///A string representation of the double's exact decimal value. public static string ToExactString (double d) { if (double.IsPositiveInfinity(d)) return "+Infinity"; if (double.IsNegativeInfinity(d)) return "-Infinity"; if (double.IsNaN(d)) return "NaN"; // Translate the double into sign, exponent and mantissa. long bits = BitConverter.DoubleToInt64Bits(d); // Note that the shift is sign-extended, hence the test against -1 not 1 bool negative = (bits < 0); int exponent = (int) ((bits >> 52) & 0x7ffL); long mantissa = bits & 0xfffffffffffffL; // Subnormal numbers; exponent is effectively one higher, // but there's no extra normalisation bit in the mantissa if (exponent==0) { exponent++; } // Normal numbers; leave exponent as it is but add extra // bit to the front of the mantissa else { mantissa = mantissa | (1L<<52); } // Bias the exponent. It's actually biased by 1023, but we're // treating the mantissa as m.0 rather than 0.m, so we need // to subtract another 52 from it. exponent -= 1075; if (mantissa == 0) { return "0"; } /* Normalize */ while((mantissa & 1) == 0) { /* i.e., Mantissa is even */ mantissa >>= 1; exponent++; } /// Construct a new decimal expansion with the mantissa ArbitraryDecimal ad = new ArbitraryDecimal (mantissa); // If the exponent is less than 0, we need to repeatedly // divide by 2 - which is the equivalent of multiplying // by 5 and dividing by 10. if (exponent < 0) { for (int i=0; i < -exponent; i++) ad.MultiplyBy(5); ad.Shift(-exponent); } // Otherwise, we need to repeatedly multiply by 2 else { for (int i=0; i < exponent; i++) ad.MultiplyBy(2); } // Finally, return the string with an appropriate sign if (negative) return "-"+ad.ToString(); else return ad.ToString(); } /// Private class used for manipulating class ArbitraryDecimal { /// Digits in the decimal expansion, one byte per digit byte[] digits; /// /// How many digits are *after* the decimal point /// int decimalPoint=0; ////// Constructs an arbitrary decimal expansion from the given long. /// The long must not be negative. /// internal ArbitraryDecimal (long x) { string tmp = x.ToString(CultureInfo.InvariantCulture); digits = new byte[tmp.Length]; for (int i=0; i < tmp.Length; i++) digits[i] = (byte) (tmp[i]-'0'); Normalize(); } ////// Multiplies the current expansion by the given amount, which should /// only be 2 or 5. /// internal void MultiplyBy(int amount) { byte[] result = new byte[digits.Length+1]; for (int i=digits.Length-1; i >= 0; i--) { int resultDigit = digits[i]*amount+result[i+1]; result[i]=(byte)(resultDigit/10); result[i+1]=(byte)(resultDigit%10); } if (result[0] != 0) { digits=result; } else { Array.Copy (result, 1, digits, 0, digits.Length); } Normalize(); } ////// Shifts the decimal point; a negative value makes /// the decimal expansion bigger (as fewer digits come after the /// decimal place) and a positive value makes the decimal /// expansion smaller. /// internal void Shift (int amount) { decimalPoint += amount; } // - Любимые цитаты:
using System;
using System.Globalization;
///
/// A class to allow the conversion of doubles to string representations of
/// their exact decimal values. The implementation aims for readability over
/// efficiency.
///
public class DoubleConverter
{
///
/// Converts the given double to a string representation of its
/// exact decimal value.
///
/// The double to convert.
///A string representation of the double's exact decimal value.
public static string ToExactString (double d)
{
if (double.IsPositiveInfinity(d))
return "+Infinity";
if (double.IsNegativeInfinity(d))
return "-Infinity";
if (double.IsNaN(d))
return "NaN";
// Translate the double into sign, exponent and mantissa.
long bits = BitConverter.DoubleToInt64Bits(d);
// Note that the shift is sign-extended, hence the test against -1 not 1
bool negative = (bits < 0);
int exponent = (int) ((bits » 52) & 0x7ffL);
long mantissa = bits & 0xfffffffffffffL;
// Subnormal numbers; exponent is effectively one higher,
// but there's no extra normalisation bit in the mantissa
if (exponent==0)
{
exponent++;
}
// Normal numbers; leave exponent as it is but add extra
// bit to the front of the mantissa
else
{
mantissa = mantissa | (1L«52);
}
// Bias the exponent. It's actually biased by 1023, but we're
// treating the mantissa as m.0 rather than 0.m, so we need
// to subtract another 52 from it.
exponent -= 1075;
if (mantissa == 0)
{
return "0";
}
/* Normalize */
while((mantissa & 1) == 0)
{ /* i.e., Mantissa is even */
mantissa »= 1;
exponent++;
}
/// Construct a new decimal expansion with the mantissa
ArbitraryDecimal ad = new ArbitraryDecimal (mantissa);
// If the exponent is less than 0, we need to repeatedly
// divide by 2 - which is the equivalent of multiplying
// by 5 and dividing by 10.
if (exponent < 0)
{
for (int i=0; i < -exponent; i++)
ad.MultiplyBy(5);
ad.Shift(-exponent);
}
// Otherwise, we need to repeatedly multiply by 2
else
{
for (int i=0; i < exponent; i++)
ad.MultiplyBy(2);
}
// Finally, return the string with an appropriate sign
if (negative)
return "-"+ad.ToString();
else
return ad.ToString();
}
///Private class used for manipulating
class ArbitraryDecimal
{
///Digits in the decimal expansion, one byte per digit
byte[] digits;
///
/// How many digits are *after* the decimal point
///
int decimalPoint=0;
///
/// Constructs an arbitrary decimal expansion from the given long.
/// The long must not be negative.
///
internal ArbitraryDecimal (long x)
{
string tmp = x.ToString(CultureInfo.InvariantCulture);
digits = new byte[tmp.Length]
