UnixとWindowsの両方で動作する64ビット整数（uint64_t）のatoiとは何ですか？

Question

私は64ビットの整数文字列を整数に変換しようとしていますが、どちらを使うべきかわかりません。

Answer 1

使用している場合はstrtoull、使用している場合は_strtoui64()を使用してください。

unsigned long long strtoull(const char *restrict str, 
     char **restrict endptr, int base); 


/* I am sure MS had a good reason not to name it "strtoull" or 
* "_strtoull" at least. 
*/ 
unsigned __int64 _strtoui64(
    const char *nptr, 
    char **endptr, 
    int base 
); 

Answer 2

strtoull()またはstrtoul()を試してください。前者はC99とC++ 11のみであるが、通常は広く入手可能である。

Answer 3

この質問はc++とタグ付けされているので、C++ソリューションにも興味があると思われます。ブーストはあなたに利用できない場合は、boost::lexical_castまたはstd::istringstreamを使用してこの操作を行うことができます。

#include <boost/lexical_cast.hpp> 
#include <sstream> 
#include <iostream> 
#include <cstdint> 
#include <string> 

int main() { 
    uint64_t test; 
    test = boost::lexical_cast<uint64_t>("594348534879"); 

    // or 
    std::istringstream ss("48543954385"); 
    if (!(ss >> test)) 
    std::cout << "failed" << std::endl; 
} 

両方のスタイルは、WindowsとLinux（など）に取り組みます。 C++ 11では

functions that operate on std::stringは、あなたが使用することができますstd::stoull含めて、もあります：

#include <string> 

int main() { 
    const std::string str="594348534879"; 
    unsigned long long v = std::stoull(str); 
} 

Answer 4

のような何か...

#ifdef WINDOWS 
    #define atoll(S) _atoi64(S) 
#endif 

..thenだけatoll()を使用しています。 #ifdef WINDOWSを何か他のものに変更したい場合は、atoll()が見つからないが、atoi64()があることを示すために頼りにできるものを使用してください（少なくともあなたが懸念しているシナリオの場合）。

Answer 5

現代のC++では、std :: stollを使用します。

http://en.cppreference.com/w/cpp/string/basic_string/stol

std::stoi, std::stol, std::stoll 
    C++ Strings library std::basic_string 
Defined in header <string> 
int  stoi(const std::string& str, std::size_t* pos = 0, int base = 10); 
int  stoi(const std::wstring& str, std::size_t* pos = 0, int base = 10); 
(1) (since C++11) 
long  stol(const std::string& str, std::size_t* pos = 0, int base = 10); 
long  stol(const std::wstring& str, std::size_t* pos = 0, int base = 10); 
(2) (since C++11) 
long long stoll(const std::string& str, std::size_t* pos = 0, int base = 10); 
long long stoll(const std::wstring& str, std::size_t* pos = 0, int base = 10); 
(3) (since C++11) 
Interprets a signed integer value in the string str. 
1) calls std::strtol(str.c_str(), &ptr, base) or std::wcstol(str.c_str(), &ptr, base) 
2) calls std::strtol(str.c_str(), &ptr, base) or std::wcstol(str.c_str(), &ptr, base) 
3) calls std::strtoll(str.c_str(), &ptr, base) or std::wcstoll(str.c_str(), &ptr, base) 
Discards any whitespace characters (as identified by calling isspace()) until the first non-whitespace character is found, then takes as many characters as possible to form a valid base-n (where n=base) integer number representation and converts them to an integer value. The valid integer value consists of the following parts: 
(optional) plus or minus sign 
(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 values for base is {0,2,3,...,36}. The set of valid digits for base-2 integers is {0,1}, for base-3 integers is {0,1,2}, 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. 
Additional numeric formats may be accepted by the currently installed C locale. 
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. 
If the minus sign was part of the input sequence, the numeric value calculated from the sequence of digits is negated as if by unary minus in the result type. 
If pos is not a null pointer, then a pointer ptr - internal to the conversion functions - will receive the address of the first unconverted character in str.c_str(), and the index of that character will be calculated and stored in *pos, giving the number of characters that were processed by the conversion. 
Parameters 
str - the string to convert 
pos - address of an integer to store the number of characters processed 
base - the number base 
Return value 
The string converted to the specified signed integer type. 
Exceptions 
std::invalid_argument if no conversion could be performed 
std::out_of_range if the converted value would fall out of the range of the result type or if the underlying function (std::strtol or std::strtoll) sets errno to ERANGE.