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std::wcstoimax, std::wcstoumax

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< cpp‎ | string‎ | wide
Revision as of 13:05, 10 April 2013 by P12 (Talk | contribs)

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Defined in header <cinttypes>
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std::intmax_t wcstoimax( const wchar_t* nptr, wchar_t** endptr, int base );
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<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

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std::uintmax_t wcstoumax( const wchar_t* nptr, wchar_t** endptr, int base );
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<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> Template:ddcl list end

Interprets an unsigned integer value in a wide string pointed to by nptr.

Function discards any whitespace characters (as identified by calling isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to form a valid base-n (where n=base) unsigned integer number representation and converts them to an integer value. The valid unsigned integer value consists of the following parts:

  • (optional) prefix (0) indicating octal base (applies only when the base is 8 or 0)
  • (optional) prefix (0x or 0X) indicating hexadecimal base (applies only when the base is 16 or 0)
  • a sequence of digits

The set of valid digits for base-2 integer is 01, for base-3 integer is 012, and so on. For bases larger than 10, valid digits include alphabetic characters, starting from Aa for base-11 integer, to Zz for base-36 integer. The case of the characters is ignored. In non-default locales, additional numeric formats may be accepted.

If the value of base is 0, the numeric base is auto-detected: if the prefix is 0, the base is octal, if the prefix is 0x or 0X, the base is hexadecimal, otherwise the base is decimal.

The functions sets the pointer pointed to by endptr to point to the wide character past the last character interpreted. If endptr is NULL, it is ignored.

Contents

Parameters

nptr - pointer to the null-terminated wide string to be interpreted
endptr - pointer to a pointer to a wide character.
base - base of the interpreted integer value

Return value

Integer 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 INTMAX_MAX, INTMAX_MIN, UINTMAX_MAX, or 0 is returned, as appropriate. If no conversion can be performed, 0 is returned.

Example

#include <iostream>
#include <string>
#include <cinttypes>
 
int main()
{
    std::wstring str = L"helloworld";
    std::intmax_t val = std::wcstoimax(str.c_str(), nullptr, 36);
    std::wcout << str << " in base 36 is " << val << " in base 10\n";
 
    wchar_t* nptr;
    val = std::wcstoimax(str.c_str(), &nptr, 30);
    if(nptr != &str[0] + str.size())
        std::wcout << str << " in base 30 is invalid."
                  << " The first invalid digit is " << *nptr << '\n';
}

Output:

helloworld in base 36 is 1767707668033969 in base 10
helloworld in base 30 is invalid. The first invalid digit is w

See also

Template:cpp/string/byte/dcl list strtoimaxTemplate:cpp/string/wide/dcl list wcstolTemplate:cpp/string/wide/dcl list wcstoul
C documentation for wcstoimax, wcstoumax