从华氏温度转换为摄氏温度
我正在尝试将华氏温度转换为摄氏温度。
做以下我总是得到零：
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace Celcius_Farenheit_Converter { class Program { static double Celcius(double f) { double c = 5/9*(f - 32); return c; } static void Main(string[] args) { string text = "enter a farenheit tempature"; double c = Celcius(GetTempature(text)); Console.WriteLine("the tempature in Celicus is {0}", c); Console.ReadKey(true); } static double GetTempature(string text) { Console.WriteLine(text); bool IsItTemp = false; double x = 0; do { IsItTemp = double.TryParse(Console.ReadLine(), out x); } while (!IsItTemp); return x; } } } 你能帮我解决一下吗？
5/9执行整数除法 – 也就是说，它总是丢弃小数部分 – 所以它总是返回0。
5.0/9.0执行浮点除法，并将返回预期的0.55555 …
试试这个：
static double Celcius(double f) { double c = 5.0/9.0 * (f - 32); return c; }
进一步阅读
- /运算符（C＃参考）
将整数除法更改为浮点除法 ;
double c = (5.0 / 9.0) * (f - 32);
来自C# Specification $7.7.2 Division operator ;
整数除法：
除法将结果舍入为零，结果的绝对值是最大可能的整数，小于两个操作数的商的绝对值。 当两个操作数具有相同符号时，结果为零或正，当两个操作数具有相反符号时，结果为零或负。
正如弗雷德里克所说 ，只将你的一个变量转换为浮点类型也足以进行计算。 （ 5 / 9f或5f / 9给出正确的解决方案）
在评论的早期，我建议使用struct来封装温度转换逻辑。 如果感兴趣的话，我已经敲了下面的粗略哈希（只是部分测试过）：
public struct Temperature: IComparable { #region fields double value; TemperatureUnit unit; #endregion fields #region constructors public Temperature(double value, TemperatureUnit unit) { AssertUnitNotNull(unit); AssertValueNotBelowAbsZero(value, unit); this.value = value; this.unit = unit; } public Temperature(Temperature temp, TemperatureUnit unit) { AssertUnitNotNull(unit); this.value = ConvertUnit(temp.value, temp.unit, unit); this.unit = unit; } #endregion constructors #region properties public double Value { get { return this.value; } set { AssertValueNotBelowAbsZero(value, this.unit); this.value = value; } } public TemperatureUnit Unit { get { return this.unit; } set { AssertUnitNotNull(value); if (this.unit != value) { this.value = ConvertUnit(this.value, this.unit, value); this.unit = value; } } } #endregion properties #region methods #region overridden methods public override bool Equals(object obj) { return this.CompareTo(obj) == 0; } public override int GetHashCode() { return this.unit.ToKelvin(value).GetHashCode(); } const string OutputFormat = "{0}{1}"; public override string ToString() { return string.Format(OutputFormat, this.value, this.unit.Symbol); } #endregion overridden methods public int CompareTo(object obj) { Temperature? t = obj as Temperature?; if (!t.HasValue) return -1; return this.unit.ToKelvin(value).CompareTo(t.Value.unit.ToKelvin(t.Value.value)); } #region operator overloads public static Temperature operator +(Temperature a, double b) { return new Temperature(a.value + b, a.unit); } public static Temperature operator +(Temperature a, Temperature b) { return a + ConvertUnit(b.value, b.unit, a.unit); } public static Temperature operator +(Temperature a, TemperatureUnit b) { return new Temperature(a, b); } public static Temperature operator -(Temperature a, double b) { return new Temperature(a.value - b, a.unit); } public static Temperature operator -(Temperature a, Temperature b) { return a - ConvertUnit(b.value, b.unit, a.unit); } public static Temperature operator ++(Temperature a) { return new Temperature(a.value + 1.0, a.unit); } public static Temperature operator --(Temperature a) { return new Temperature(a.value - 1.0, a.unit); } public static Temperature operator /(Temperature a, double b) { return new Temperature(a.value / b, a.unit); } public static Temperature operator *(Temperature a, double b) { return new Temperature(a.value * b, a.unit); } #endregion operator overloads #region helper methods private static double ConvertUnit(double value, TemperatureUnit from, TemperatureUnit to) { return to.FromKelvin(from.ToKelvin(value)); } #endregion helper methods #endregion methods #region static validation methods private static void AssertUnitNotNull(TemperatureUnit unit) { if (unit == null) throw new ArgumentNullException(); } private static void AssertValueNotBelowAbsZero(double value, TemperatureUnit unit) { if (unit.ToKelvin(value) < 0.0) throw new TemperatureIsBelowAbsoluteZeroException(value,unit); } #endregion static validation methods } public sealed class TemperatureUnit { #region delegate definitions delegate double Conversion(double source); #endregion delegate definitions #region attributes readonly string name; readonly string symbol; //base all functions around Kelvin since that allows us to restrict values to zero and above readonly Conversion fromKelvin; readonly Conversion toKelvin; #endregion attributes #region constructors private TemperatureUnit(string name, string symbol, Conversion fromKelvin, Conversion toKelvin) { this.name = name; this.symbol = symbol; this.fromKelvin = fromKelvin; this.toKelvin = toKelvin; } #endregion constructors #region properties public string Name { get { return this.name; } } public string Symbol { get { return this.symbol; } } #region defined units public static TemperatureUnit Kelvin = new TemperatureUnit("Kelvin", "\u212A", delegate(double d) { return d; }, delegate(double d) { return d; }); public static TemperatureUnit Celcius = new TemperatureUnit("Celcius", "\u2103", KelvinToCelcius, CelciusToKelvin); public static TemperatureUnit Farenheit = new TemperatureUnit("Farenheit", "\u2109", KelvinToFarenheit, FarenheitToKelvin); public static TemperatureUnit Rankine = new TemperatureUnit("Rankine", "\u00B0Ra", KelvinToRankine, RankineToKelvin); public static TemperatureUnit Romer = new TemperatureUnit("R\u03B8mer", "\u00B0R\u03B8", KelvinToRomer, RomerToKelvin); public static TemperatureUnit Newton = new TemperatureUnit("Newton", "\u00B0N", KelvinToNewton, NewtonToKelvin); public static TemperatureUnit Delisle = new TemperatureUnit("Delisle", "\u00B0D", KelvinToDelisle, DelisleToKelvin); public static TemperatureUnit Reaumur = new TemperatureUnit("R\u00E9amur", "\u00B0R\u00E9", KelvinToReaumur, ReaumurToKelvin); #endregion defined units #endregion properties #region functions public double FromKelvin(double kelvin) { return this.fromKelvin(kelvin); } public double ToKelvin(double value) { return this.toKelvin(value); } #endregion functions #region overridden methods public override bool Equals(object obj) { TemperatureUnit tu = obj as TemperatureUnit; if (tu == null) return false; return this.name.Equals(tu.name); } public override int GetHashCode() { return this.name.GetHashCode(); } public override string ToString() { return this.name.ToString(); } #endregion overridden methods #region static conversion functions #region Celcius const double KelvinToCelciusOffset = -273.15; public static double CelciusToKelvin(double celcius) { return celcius - KelvinToCelciusOffset; } public static double KelvinToCelcius(double kelvin) { return kelvin + KelvinToCelciusOffset; } #endregion Celcius #region Fahrenheit //Fahrenheit [°F] = [K] × 9⁄5 − 459.67 [K] = ([°F] + 459.67) × 5⁄9 const double KelvinToFarenheitMultiplier = 9.0 / 5.0; const double KelvinToFarenheitOffset = -459.67; public static double FarenheitToKelvin(double farenheit) { return (farenheit - KelvinToFarenheitOffset) / KelvinToFarenheitMultiplier; } public static double KelvinToFarenheit(double kelvin) { return kelvin * KelvinToFarenheitMultiplier + KelvinToFarenheitOffset; } #endregion Fahrenheit #region Rankine const double KelvinToRankineMultiplier = KelvinToFarenheitMultiplier; public static double RankineToKelvin(double rankine) { return rankine / KelvinToRankineMultiplier; } public static double KelvinToRankine(double kelvin) { return kelvin * KelvinToRankineMultiplier; } #endregion Rankine #region Romer //[K] = ([°Rø] − 7.5) × 40⁄21 + 273.15 [°Rø] = ([K] − 273.15) × 21⁄40 + 7.5 const double KelvinToRomerMultiplier = 21.0 / 40.0; const double KelvinToRomerOffset1 = KelvinToCelciusOffset; const double KelvinToRomerOffset2 = 7.5; public static double RomerToKelvin(double romer) { return (romer - KelvinToRomerOffset2) / KelvinToRomerMultiplier - KelvinToRomerOffset1; } public static double KelvinToRomer(double kelvin) { return (kelvin + KelvinToRomerOffset1) * KelvinToRomerMultiplier + KelvinToRomerOffset2; } #endregion Romer #region Newton //[K] = [°N] × 100⁄33 + 273.15 [°N] = ([K] − 273.15) × 33⁄100 const double KelvinToNewtonMultiplier = 33.0 / 100.0; const double KelvinToNewtonOffset = KelvinToCelciusOffset; public static double NewtonToKelvin(double newton) { return (newton / KelvinToNewtonMultiplier) - KelvinToNewtonOffset; } public static double KelvinToNewton(double kelvin) { return (kelvin + KelvinToNewtonOffset) * KelvinToNewtonMultiplier; } #endregion Newton #region Delisle //[K] = 373.15 − [°De] × 2⁄3 [°De] = (373.15 − [K]) × 3⁄2 const double KelvinToDelisleMultiplier = 1.5; const double KelvinToDelisleOffset = 373.15; public static double DelisleToKelvin(double delisle) { return KelvinToDelisleOffset - delisle / KelvinToDelisleMultiplier; } public static double KelvinToDelisle(double kelvin) { return (KelvinToDelisleOffset - kelvin) * KelvinToDelisleMultiplier; } #endregion Delisle #region Reaumur //[K] = [°Ré] × 5⁄4 + 273.15 [°Ré] = ([K] − 273.15) × 4⁄5 const double KelvinToReaumurMultiplier = 4.0 / 5.0; const double KelvinToReaumurOffset = KelvinToCelciusOffset; public static double ReaumurToKelvin(double reaumur) { return reaumur / KelvinToReaumurMultiplier - KelvinToReaumurOffset; } public static double KelvinToReaumur(double kelvin) { return (kelvin + KelvinToReaumurOffset) * KelvinToReaumurMultiplier; } #endregion Reaumur #endregion static conversion functions } public class TemperatureIsBelowAbsoluteZeroException : Exception { public TemperatureIsBelowAbsoluteZeroException() : base() { } public TemperatureIsBelowAbsoluteZeroException(string message) : base(message) { } public TemperatureIsBelowAbsoluteZeroException(string message, Exception innerException) : base(message,innerException) { } public TemperatureIsBelowAbsoluteZeroException(System.Runtime.Serialization.SerializationInfo info,System.Runtime.Serialization.StreamingContext context) : base(info,context) { } const string ErrorMessageFormat = "Value '{0}{1}' is below absolute zero!"; public TemperatureIsBelowAbsoluteZeroException(double value, TemperatureUnit unit) : base(string.Format(ErrorMessageFormat, value, unit.Symbol)) { } }
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class TempConvert { static void Main(string[] args) { //Variables declared to hold and test conversion //floats used to avoid int calculation errors float originalFarenheit; float centigrade; float returnFarenheit; Console.Write("Enter Temperature (Farenheit): "); //take temp to be converted originalFarenheit = float.Parse(Console.ReadLine()); //hold as float var centigrade = ((originalFarenheit - 32) / 9) * 5; //Convert to centrigrade returnFarenheit = ((centigrade / 5) * 9) + 32; //test conversion by reversing Console.WriteLine("Centigrade = :" + centigrade); //Display result Console.WriteLine("Return Farenheit = :" + returnFarenheit); //Test result Console.ReadKey(); } } }
这是一种通用方法，可执行所有温度单位转换
public static double ConvertTemperatureUnits(TemperatureUnit toConvert, TemperatureUnit from, double value) { double convertedValue = 0.0; if (toConvert == from) return value; switch (toConvert) { case TemperatureUnit.FAHRENHEIT: { switch (from) { case TemperatureUnit.CELSIUS: convertedValue = (value * 9) / 5 + 32; break; case TemperatureUnit.KELVIN: convertedValue = 1.8 * (value - 273.15) + 32; break; } } break; case TemperatureUnit.KELVIN: switch (from) { case TemperatureUnit.CELSIUS: convertedValue = value + 273.15; break; case TemperatureUnit.FAHRENHEIT: convertedValue = (value + 459.67) * 5 / 9; break; } break; case TemperatureUnit.CELSIUS: switch (from) { case TemperatureUnit.KELVIN: convertedValue = value - 273.15; break; case TemperatureUnit.FAHRENHEIT: convertedValue = (value - 32) * 5 / 9; break; } break; } return convertedValue; }
像这样创建TemperatureUnit枚举
enum TemperatureUnit { FAHRENHEIT, KELVIN, CELSIUS }