std::stoi, std::stol, std::stoll
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
.
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 or 0) - (optional) prefix (
0x
or0X
) 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.
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 pos
is passed a value other than 0 or nullptr, then a pointer ptr
- internal to the conversion functions - will receive the address of the first unconverted character, and the index of that character will be calculated and stored in *pos
.
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
- 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.
[edit] Example
#include <iostream> #include <string> int main() { std::string str1 = "45"; std::string str2 = "3.14159"; std::string str3 = "31337 with words"; std::string str4 = "words and 2"; int myint1 = std::stoi(str1); int myint2 = std::stoi(str2); int myint3 = std::stoi(str3); // error: 'std::invalid_argument' // int myint4 = std::stoi(str4); std::cout << "std::stoi(\"" << str1 << "\") is " << myint1 << '\n'; std::cout << "std::stoi(\"" << str2 << "\") is " << myint2 << '\n'; std::cout << "std::stoi(\"" << str3 << "\") is " << myint3 << '\n'; //std::cout << "std::stoi(\"" << str4 << "\") is " << myint4 << '\n'; }
Output:
std::stoi("45") is 45 std::stoi("3.14159") is 3 std::stoi("31337 with words") is 31337
[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 a floating point value (function) |
(C++11)
|
converts an integral or floating point value to string (function) |