If you don't want to accept strings like "32asd" as valid you need to wrap strtod in a function such as this:If it is a c-string (null-terminated array of type char), you can do something like:If it is a C++ string, just use the c_str() method:atof() will convert the string to a double, returning 0 on failure.

Die verbleibenden System.Globalization.NumberStyles Member … Convert string to double. This example program demonstrates how to convert a string to a double (floating point value) in C using atof and strtof . It has 15 decimal digits of precision. The strtod function skips all white-space characters at the beginning of the string, converts the subsequent characters as part of the number, and then stops when it encounters the first character that isn't a number.The syntax for the strtod function in the C Language is:The strtod function returns the double representation of a string. Das Problem einen Double in einen String umzuwandeln um ihn später (ggfs. nach Änderung) wieder zurück ein einen Double umzuwandeln ist nicht besonders groß.

Das gleiche Programm mit anderen Ländereinstellungen kann zu falschen Werten führen (aus 99,99 werden dann schnell 9999 Euro).

Abhilfe schafft hier "InvariantCulture".

Hier der zweite Teil : String … Then, we set some important properties for this object like NumberDecimalSeparator and NumberGroupSeparator.Example showing the conversion of string to double using Convert.ToDouble() method.Example showing the conversion from string to double using Double.TryParse() method.Example showing scenario when the string to be converted to double is either ‘null’ or empty.This is a guide to Convert String to Double in C#. In the same way, we can convert a string to double using a method present inside the “Convert” class called ToDouble() method.
The strtod function returns the double representation of a string. Using the ToDouble(String) method is equivalent to passing value to the Double.Parse(String) method. You can then catch the bad_lexical_cast that might occure, and do something when it fails, instead of getting 0.0 which atof gives.One of the most elegant solution to this problem is to use boost::lexical_cast as @Evgeny Lazin mentioned.However, it does try to parse as much of the string as it can. By clicking “Post Your Answer”, you agree to our To subscribe to this RSS feed, copy and paste this URL into your RSS reader. ALL RIGHTS RESERVED. to nothing, leaving only the number … Parses the C string str, interpreting its content as a floating point number and returns its value as a double. The function is documented here: Since C++11 converting string to floating-point values (like double) is available with functions:I want a function that returns 0 when the string is not numerical.Must say I agree with that the most elegant solution to this is using boost::lexical_cast. Double. If idx is not a null pointer, the function also sets the value of idx to the position of the first character in str after the number. Where developers & technologists share private knowledge with coworkersProgramming & related technical career opportunitiesYou should give this a more descriptive title or no one will help.How about some of the examples from the following: Exception handling should not be used for flow control. The following example converts each element in an array of UInt64 values to a Double value.. ulong[] numbers = { UInt64.MinValue, 121, 12345, UInt64.MaxValue }; double result; foreach (ulong number in numbers) { result = Convert.ToDouble(number); Console.WriteLine("Converted the UInt64 value {0} to {1}. As long as my_string most usually contains a number, then I'd say this fits the bill as an Unfortunately this will look like it works for "10.5xxxx". If endptr is not NULL, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr. Double is also a datatype which is used to represent the floating point numbers. Convert string to double. There are many overloaded forms of this method and among those overloaded forms, we have two forms to convert a string representation of a number to its equivalent double-precision floating-point number.Both these methods return a double value after converting the string value to double.The syntax of Convert.ToDouble() method in both its overloaded forms for converting a string to double is as follows:In the above syntax, ToDouble() method takes one argument of type string (In the above syntax, ToDouble() method takes two arguments; the first is the string representation of a number which needs to be converted to double and second is an object which provides culture-specific formatting information. If the strtod function converts a value that is too large or too small to convert, it will store ERANGE in errono. Stack Overflow for Teams is a private, secure spot for you and or should it return 10.5?note the empty string will be accepted by that code :) (endptr == str || *endptr) should fix it In C#, almost all types of data can be converted to any other type. The function uses strtod (or wcstod) to perform the conversion (see strtod for more details on the process). If str is a character vector or string scalar, then X …
In C#, the “System” namespace contains a class called “Convert” which contains the ToDouble() method in many overloaded forms to convert the specified type of data to its equivalent double value. value is interpreted by using the formatting conventions of the current thread culture. Free 30 Day Trial Here is the syntax of double in C language, double variable_name; Here is an example of double in C language, Example. Syntax.

The C library function double strtod (const char *str, char **endptr) converts the string pointed to by the argument str to a floating-point number (type double).