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

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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.

Contents

[edit] Parameters

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

[edit] Return value

The string converted to the specified signed integer type.

[edit] Exceptions

[edit] Example

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

Output:

45

[edit] See also

converts a byte string to an integer value
(function)
(C++11)
(C++11)
converts a string to an unsigned integer
(function)
(C++11)
(C++11)
(C++11)
converts a string to an floating point value
(function)
(C++11)
converts an integral or floating point value to string
(function)