numeric-conversion | 易学教程

C++ how to set a fixed decimal precision for a float

阅读更多关于 C++ how to set a fixed decimal precision for a float

问题 I have an API call which returns a double. The double's decimal length can variate from many decimal places to a few (it all comes down to the state of an actuator). This double represents the current position on the range radius of an actuator. I am not interested in such a detailed number, because it adds alot of noise to the system. I've been using floats to save space, but still I have floats which have 6-8 decimal length. I am not interested in floor or ceil, simply because it doesn't do

C++ how to set a fixed decimal precision for a float

阅读更多关于 C++ how to set a fixed decimal precision for a float

SQL Server CONVERT(NUMERIC(18,0), '') fails but CONVERT(INT, '') succeeds?

阅读更多关于 SQL Server CONVERT(NUMERIC(18,0), '') fails but CONVERT(INT, '') succeeds?

问题 PRINT CONVERT(NUMERIC(18,0), '') produces Error converting data type varchar to numeric. However, PRINT CONVERT(INT, '') produces 0 without error... Question: Is there some SQL Server flag for this or will I need to do case statements for every varchar to numeric conversion? (aside from the obvious why?) 回答1: Use ISNUMERIC declare @a varchar(20) set @a = 'notanumber' select case when isnumeric(@a) = 0 then 0 else convert(numeric(18,0),@a) end 回答2: ISNUMERIC doesn't alway work as you might

How do I convert the value of a TextView to integer

阅读更多关于 How do I convert the value of a TextView to integer

问题 I am designing a basic BMI calculator and I have the calculator working, but I need to convert the calculated answer from a TextView which is a double to an integer to enable me right statements with <> operators based on the calculated answer. How do I convert the answer from the TextView to an integer? v.findViewById(R.id.bmi).setOnClickListener(this); return v; } public void onClick(View v) { switch (v.getId()) { case R.id.bmi: try { EditText w = (EditText) getView().findViewById(R.id.w);

convert Arabic numerical to English

阅读更多关于 convert Arabic numerical to English

问题 i am looking for a way to convert the Arabic numerical string "٠١٢٣٤٥٦٧٨٩" to an English numerical string "0123456789" Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click dim Anum as string ="٠١٢٣٤٥٦٧٨٩" dim Enum as string =get_egnlishNum(Anum) End Sub private function get_egnlishNum(byval _Anum as string) as string '' converting code end function 回答1: You're looking for the GetNumericValue method of the char type which converts any

Best practice in C++ for casting between number types [duplicate]

阅读更多关于 Best practice in C++ for casting between number types [duplicate]

问题 This question already has answers here : When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used? (8 answers) Closed 3 years ago . What is the best practice for casting between the different number types? Types float , double , int are the ones I use the most in C++. An example of the options where f is a float and n is a double or an int : float f = static_cast<float>(n); float f = float(n); float f = (float)n; I usually write static_cast<T>(...) but wondered if there

Best practice in C++ for casting between number types [duplicate]

阅读更多关于 Best practice in C++ for casting between number types [duplicate]

This question already has an answer here: When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used? 8 answers What is the best practice for casting between the different number types? Types float , double , int are the ones I use the most in C++. An example of the options where f is a float and n is a double or an int : float f = static_cast<float>(n); float f = float(n); float f = (float)n; I usually write static_cast<T>(...) but wondered if there was any consensus within the C++ development community if there is a preferred way. I appreciate this is may end up being an

convert (long mantissa) and (sbyte exponent) to decimal

阅读更多关于 convert (long mantissa) and (sbyte exponent) to decimal

upd placed my version in the description at the end I need to convert mantissa and exponent to decimal. This is how I coded that: // long field.Decimal.Mantissa // sbyte field.Decimal.Exponent decimal MDEntryPx = field.Decimal.Mantissa * (decimal)(Math.Pow(10, field.Decimal.Exponent)); field.Decimal.Mantissa is integer but Math.Pow(10, field.Decimal.Exponent) is double so I afraid that I can lost precision when casting to decimal. Should I write my own Pow function for integer types that will produce decimal ? What would you suggest? I care about perfomance as I call this functions dozen of

convert (long mantissa) and (sbyte exponent) to decimal

阅读更多关于 convert (long mantissa) and (sbyte exponent) to decimal

问题 upd placed my version in the description at the end I need to convert mantissa and exponent to decimal. This is how I coded that: // long field.Decimal.Mantissa // sbyte field.Decimal.Exponent decimal MDEntryPx = field.Decimal.Mantissa * (decimal)(Math.Pow(10, field.Decimal.Exponent)); field.Decimal.Mantissa is integer but Math.Pow(10, field.Decimal.Exponent) is double so I afraid that I can lost precision when casting to decimal. Should I write my own Pow function for integer types that will

Is it more efficient to perform a range check by casting to uint instead of checking for negative values?

阅读更多关于 Is it more efficient to perform a range check by casting to uint instead of checking for negative values?

I stumbled upon this piece of code in .NET's List source code : // Following trick can reduce the range check by one if ((uint) index >= (uint)_size) { ThrowHelper.ThrowArgumentOutOfRangeException(); } Apparently this is more efficient (?) than if (index < 0 || index >= _size) I am curious about the rationale behind the trick. Is a single branch instruction really more expensive than two conversions to uint ? Or is there some other optimization going on that will make this code faster than an additional numeric comparison? To address the elephant in the room: yes, this is micro optimization,