std::wcstold
std::wcstof, std::wcstod, std::wcstold
| Defined in header | | |
|---|---|---|
| float wcstof( const wchar_t* str, wchar_t** str_end | | (since C++11) |
| double wcstod( const wchar_t* str, wchar_t** str_end | | |
| long double wcstold( const wchar_t* str, wchar_t** str_end | | (since C++11) |
Interprets a floating point value in a wide string pointed to by str.
Function discards any whitespace characters (as determined by std::isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to form a valid floating-point representation and converts them to a floating-point value. The valid floating-point value can be one of the following:
- decimal floating-point expression. It consists of the following parts:
The functions sets the pointer pointed to by str_end to point to the wide character past the last character interpreted. If str_end is NULL, it is ignored.
Parameters
| str | - | pointer to the null-terminated wide string to be interpreted |
|---|---|---|
| str_end | - | pointer to a pointer to a wide character. |
Return value
Floating point value corresponding to the contents of str on success. If the converted value falls out of range of corresponding return type, range error occurs and HUGE_VAL, HUGE_VALF or HUGE_VALL is returned. If no conversion can be performed, 0 is returned.
Example
#include <iostream>
#include <string>
#include <cerrno>
#include <cwchar>
int main()
{
const wchar_t* p = L"111.11 -2.22 0X1.BC70A3D70A3D7P+6 1.18973e+4932zzz";
wchar_t* end;
std::wcout << "Parsing L\"" << p << "\":\n";
for (double f = std::wcstod(p, &end p != end; f = std::wcstod(p, &end))
{
std::wcout << "'" << std::wstring(p, end-p) << "' -> ";
p = end;
if (errno == ERANGE){
std::wcout << "range error, got ";
errno = 0;
}
std::wcout << f << '\n';
}
}
Output:
Parsing L"111.11 -2.22 0X1.BC70A3D70A3D7P+6 1.18973e+4932zzz":
'111.11' -> 111.11
' -2.22' -> -2.22
' 0X1.BC70A3D70A3D7P+6' -> 111.11
' 1.18973e+4932' -> range error, got inf
See also
| strtofstrtodstrtold | converts a byte string to a floating point value (function) |
|---|
| C documentation for wcstof |
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