24 Strings library [strings]

24.3 String classes [string.classes]

24.3.4 Numeric conversions [string.conversions]

int stoi(const string& str, size_t* idx = nullptr, int base = 10); long stol(const string& str, size_t* idx = nullptr, int base = 10); unsigned long stoul(const string& str, size_t* idx = nullptr, int base = 10); long long stoll(const string& str, size_t* idx = nullptr, int base = 10); unsigned long long stoull(const string& str, size_t* idx = nullptr, int base = 10);
Effects: The first two functions call strtol(str.c_­str(), ptr, base), and the last three functions call strtoul(str.c_­str(), ptr, base), strtoll(str.c_­str(), ptr, base), and strtoull(​str.c_­str(), ptr, base), respectively.
Each function returns the converted result, if any.
The argument ptr designates a pointer to an object internal to the function that is used to determine what to store at *idx.
If the function does not throw an exception and idx != 0, the function stores in *idx the index of the first unconverted element of str.
Returns: The converted result.
Throws: invalid_­argument if strtol, strtoul, strtoll, or strtoull reports that no conversion could be performed.
Throws out_­of_­range if strtol, strtoul, strtoll or strtoull sets errno to ERANGE, or if the converted value is outside the range of representable values for the return type.
float stof(const string& str, size_t* idx = nullptr); double stod(const string& str, size_t* idx = nullptr); long double stold(const string& str, size_t* idx = nullptr);
Effects: These functions call strtof(str.c_­str(), ptr), strtod(str.c_­str(), ptr), and strtold(​str.c_­str(), ptr), respectively.
Each function returns the converted result, if any.
The argument ptr designates a pointer to an object internal to the function that is used to determine what to store at *idx.
If the function does not throw an exception and idx != 0, the function stores in *idx the index of the first unconverted element of str.
Returns: The converted result.
Throws: invalid_­argument if strtof, strtod, or strtold reports that no conversion could be performed.
Throws out_­of_­range if strtof, strtod, or strtold sets errno to ERANGE or if the converted value is outside the range of representable values for the return type.
string to_string(int val); string to_string(unsigned val); string to_string(long val); string to_string(unsigned long val); string to_string(long long val); string to_string(unsigned long long val); string to_string(float val); string to_string(double val); string to_string(long double val);
Returns: Each function returns a string object holding the character representation of the value of its argument that would be generated by calling sprintf(buf, fmt, val) with a format specifier of "%d", "%u", "%ld", "%lu", "%lld", "%llu", "%f", "%f", or "%Lf", respectively, where buf designates an internal character buffer of sufficient size.
int stoi(const wstring& str, size_t* idx = nullptr, int base = 10); long stol(const wstring& str, size_t* idx = nullptr, int base = 10); unsigned long stoul(const wstring& str, size_t* idx = nullptr, int base = 10); long long stoll(const wstring& str, size_t* idx = nullptr, int base = 10); unsigned long long stoull(const wstring& str, size_t* idx = nullptr, int base = 10);
Effects: The first two functions call wcstol(str.c_­str(), ptr, base), and the last three functions call wcstoul(str.c_­str(), ptr, base), wcstoll(str.c_­str(), ptr, base), and wcstoull(​str.c_­str(), ptr, base), respectively.
Each function returns the converted result, if any.
The argument ptr designates a pointer to an object internal to the function that is used to determine what to store at *idx.
If the function does not throw an exception and idx != 0, the function stores in *idx the index of the first unconverted element of str.
Returns: The converted result.
Throws: invalid_­argument if wcstol, wcstoul, wcstoll, or wcstoull reports that no conversion could be performed.
Throws out_­of_­range if the converted value is outside the range of representable values for the return type.
float stof(const wstring& str, size_t* idx = nullptr); double stod(const wstring& str, size_t* idx = nullptr); long double stold(const wstring& str, size_t* idx = nullptr);
Effects: These functions call wcstof(str.c_­str(), ptr), wcstod(str.c_­str(), ptr), and wcstold(​str.c_­str(), ptr), respectively.
Each function returns the converted result, if any.
The argument ptr designates a pointer to an object internal to the function that is used to determine what to store at *idx.
If the function does not throw an exception and idx != 0, the function stores in *idx the index of the first unconverted element of str.
Returns: The converted result.
Throws: invalid_­argument if wcstof, wcstod, or wcstold reports that no conversion could be performed.
Throws out_­of_­range if wcstof, wcstod, or wcstold sets errno to ERANGE.
wstring to_wstring(int val); wstring to_wstring(unsigned val); wstring to_wstring(long val); wstring to_wstring(unsigned long val); wstring to_wstring(long long val); wstring to_wstring(unsigned long long val); wstring to_wstring(float val); wstring to_wstring(double val); wstring to_wstring(long double val);
Returns: Each function returns a wstring object holding the character representation of the value of its argument that would be generated by calling swprintf(buf, buffsz, fmt, val) with a format specifier of L"%d", L"%u", L"%ld", L"%lu", L"%lld", L"%llu", L"%f", L"%f", or L"%Lf", respectively, where buf designates an internal character buffer of sufficient size buffsz.