std::stoi, std::stol, std::stoll

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

char_traits

 

std::basic_string

Member functions basic_string::basic_string basic_string::operator= basic_string::assign basic_string::get_allocator Element access basic_string::at basic_string::operator[] basic_string::front (C++11) basic_string::back (C++11) basic_string::data basic_string::c_str Iterators basic_string::begin basic_string::cbegin (C++11) basic_string::end basic_string::cend (C++11) basic_string::rbegin basic_string::crbegin (C++11) basic_string::rend basic_string::crend (C++11) Capacity basic_string::empty basic_string::size basic_string::length basic_string::max_size basic_string::reserve basic_string::capacity basic_string::shrink_to_fit (C++11)	Operations basic_string::clear basic_string::insert basic_string::erase basic_string::push_back basic_string::pop_back (C++11) basic_string::append basic_string::operator+= basic_string::compare basic_string::replace basic_string::substr basic_string::copy basic_string::resize basic_string::swap Search basic_string::find basic_string::rfind basic_string::find_first_of basic_string::find_first_not_of basic_string::find_last_of basic_string::find_last_not_of Constants basic_string::npos	Non-member functions operator+ operator== operator!= operator< operator> operator<= operator>= swap(std::basic_string) operator<< operator>> getline stoi stol stoll (C++11) (C++11) (C++11) stoul stoull (C++11) (C++11) stof stod stold (C++11) (C++11) (C++11) to_string (C++11) to_wstring (C++11) Helper classes hash<std::string> hash<std::wstring> hash<std::u32string> hash<std::u16string> (C++11)

 

Defined in header <string>
int       stoi( const std::string& str, size_t *pos = 0, int base = 10 );	(1)	(since C++11)
long      stol( const std::string& str, size_t *pos = 0, int base = 10 );	(2)	(since C++11)
long long stoll( const std::string& str, size_t *pos = 0, int base = 10 );	(3)	(since C++11)

Interprets a signed integer value in the string str.

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) 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)
• (optional) prefix (0x or 0X) indicating hexadecimal base (applies only when the base is 16)
• 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 index of the first unconverted character is stored in pos. If NULL is passed as pos, it is ignored.

Parameters

str	-	the string to convert
pos	-	address of an integer to store the index of the first unconverted character
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.

Example

run this code

#include <iostream>
#include <string>
 
int main()
{
    std::string test = "45";
    int myint = std::stoi(test);
    std::cout << myint << '\n';
}

Output:

45

See also

atoi atol atoll	converts a byte string to an integer value (function)
stoul stoull (C++11) (C++11)	converts a string to an unsigned integer (function)
stof stod stold (C++11) (C++11) (C++11)	converts a string to an floating point value (function)
to_string (C++11)	converts an integral or floating point value to string (function)