I'm doing a simple program for converting temperatures with Kelvin, Celsius and Fahrenheit, but I'm getting this error when doing anything with kelvin:
我正在做一个用开尔文,摄氏和华氏温度转换温度的简单程序,但是在用开尔文做任何事情时我都会遇到这个错误:
Cannon implicitly convert type 'double' to 'float'
The line the error occurs:
发生错误的行:
public static float FahrenheitToKelvin(float fahrenheit)
{
return ((fahrenheit - 32) * 5) / 9 + 273.15;
}
The button click:
按钮点击:
private void button1_Click(object sender, EventArgs e)
{
var input = float.Parse(textBox1.Text);
float FahrenResult = FahrenheitToCelsius(input);
textBox2.Text = FahrenResult.ToString();
float KelvinResult = FahrenheitToKelvin(input);
textBox3.Text = KelvinResult.ToString();
}
And the test method I'm trying to make:
我试图做的测试方法:
[TestMethod]
public void fahrenheitToKelvinBoiling()
{
float fahrenheit = 212F;
float expected = 373.15F; // TODO: Initialize to an appropriate value
float actual;
actual = Form1.FahrenheitToKelvin(fahrenheit);
Assert.AreEqual(Math.Round(expected, 2), Math.Round(actual, 2));
// Assert.Inconclusive("Verify the correctness of this test method.");
}
2 个解决方案
#1
8
Try this.
public static float FahrenheitToKelvin(float fahrenheit)
{
return ((fahrenheit - 32f) * 5f) / 9f + 273.15f;
}
This works because it changes the compiler from recognizing the 32 5 and so on as doubles. The f after the number tells the compiler it is a float.
这是有效的,因为它将编译器从识别32 5等改为双倍。数字后面的f告诉编译器它是一个浮点数。
#2
0
The compiler is promoting the resulting expression to a double. I think it assumes that those numbers which includes a decimal part are double.
编译器将结果表达式提升为double。我认为它假定那些包含小数部分的数字是双倍的。
Nevertheless you can explicitly convert the resulting value to a float;
不过,您可以将结果值显式转换为浮点数;
or you can try to explicitly convert all your constants that have a decimal separator to a float.
或者您可以尝试将具有小数分隔符的所有常量显式转换为float。
EDIT
As a side note, are you perfectly comfortable with using a floats (or doubles) instead of decimals? I don't see your code, eventually when displaying data to the user interface by invoking the ToString() method, rounding the value to a certain number of precision digits (although your unit test does it).
作为旁注,你是否完全适合使用花车(或双打)而不是小数?我没有看到你的代码,最终通过调用ToString()方法将数据显示到用户界面,将值四舍五入到一定数量的精确数字(尽管你的单元测试是这样做的)。
You might get some "lost" precision digits at the end of you float and they'll get displayed to the UI by using ToString().
您可能会在浮动结束时获得一些“丢失”的精确数字,并且它们将通过使用ToString()显示到UI。
I'd strongly suggest either:
我强烈建议:
- Use round to a certain decimal precision
- Change the floats to decimals
使用舍入到某个小数精度
将浮点数更改为小数
#1
8
Try this.
public static float FahrenheitToKelvin(float fahrenheit)
{
return ((fahrenheit - 32f) * 5f) / 9f + 273.15f;
}
This works because it changes the compiler from recognizing the 32 5 and so on as doubles. The f after the number tells the compiler it is a float.
这是有效的,因为它将编译器从识别32 5等改为双倍。数字后面的f告诉编译器它是一个浮点数。
#2
0
The compiler is promoting the resulting expression to a double. I think it assumes that those numbers which includes a decimal part are double.
编译器将结果表达式提升为double。我认为它假定那些包含小数部分的数字是双倍的。
Nevertheless you can explicitly convert the resulting value to a float;
不过,您可以将结果值显式转换为浮点数;
or you can try to explicitly convert all your constants that have a decimal separator to a float.
或者您可以尝试将具有小数分隔符的所有常量显式转换为float。
EDIT
As a side note, are you perfectly comfortable with using a floats (or doubles) instead of decimals? I don't see your code, eventually when displaying data to the user interface by invoking the ToString() method, rounding the value to a certain number of precision digits (although your unit test does it).
作为旁注,你是否完全适合使用花车(或双打)而不是小数?我没有看到你的代码,最终通过调用ToString()方法将数据显示到用户界面,将值四舍五入到一定数量的精确数字(尽管你的单元测试是这样做的)。
You might get some "lost" precision digits at the end of you float and they'll get displayed to the UI by using ToString().
您可能会在浮动结束时获得一些“丢失”的精确数字,并且它们将通过使用ToString()显示到UI。
I'd strongly suggest either:
我强烈建议:
- Use round to a certain decimal precision
- Change the floats to decimals
使用舍入到某个小数精度
将浮点数更改为小数