21 Strings library [strings]

21.3 String classes [string.classes]

21.3.5 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 != nullptr, 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.

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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 != nullptr, 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.

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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.

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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 != nullptr, 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.

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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 != nullptr, 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.

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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.