function template
<string>

std::stoull

unsigned long long stoull (const string&  str, size_t* idx = 0, int base = 10);
unsigned long long stoull (const wstring& str, size_t* idx = 0, int base = 10);
Convert string to unsigned long long
Parses str interpreting its content as an integral number of the specified base, which is returned as a value of type unsigned long long.

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.

The function uses strtoull (or wcstoull) to perform the conversion (see strtol for more details on the process).

Parameters

str
String object with the representation of an integral number.
idx
Pointer to an object of type size_t, whose value is set by the function to position of the next character in str after the numerical value.
This parameter can also be a null pointer, in which case it is not used.
base
Numerical base (radix) that determines the valid characters and their interpretation.
If this is 0, the base used is determined by the format in the sequence (see strtol for details). Notice that by default this argument is 10, not 0.

Return Value

On success, the function returns the converted integral number as a value of type unsigned long long.

Example

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// stoull example
#include <iostream>   // std::cout
#include <string>     // std::string, std::stoull

int main ()
{
  std::string str = "8246821 0xffff 020 -1";

  std::string::size_type sz = 0;   // alias of size_t

  while (!str.empty()) {
    unsigned long long ull = std::stoull (str,&sz,0);
    std::cout << str.substr(0,sz) << " interpreted as " << ull << '\n';
    str = str.substr(sz);
  }

  return 0;
}


Possible output:
8246821 interpreted as 8246821
 0xffff interpreted as 65535
 020 interpreted as 16
 -1 interpreted as 18446744073709551615

Complexity

Unspecified, but generally linear in the number of characters interpreted.

Data races

Modifies the value pointed by idx (if not zero).

Exceptions

If no conversion could be performed, an invalid_argument exception is thrown.
If the value read is out of the range of representable values by a unsigned long long, an out_of_range exception is thrown.

An invalid idx causes undefined behavior.

See also

stoi
Convert string to integer (function template )
stoul
Convert string to unsigned integer (function template )
stoll
Convert string to long long (function template )
strtoull
Convert string to unsigned long long integer (function )