std::stof, std::stod, std::stold
From cppreference.com
< cpp | string | basic string
| Defined in header <string>
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| float stof( const std::string& str, size_t *pos = 0 );
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(1) | (since C++11) |
| double stod( const std::string& str, size_t *pos = 0 );
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(2) | (since C++11) |
| long double stold( const std::string& str, size_t *pos = 0 );
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(3) | (since C++11) |
Interprets a floating point value in a string str.
Function discards any whitespace characters (as determined by std::isspace()) until first non-whitespace character is found. Then it takes as many characters as possible to form a valid floating point representation and converts them to floating point value. The valid floating point value can be one of the following:
- decimal floating point expression. It consists of the following parts:
- (optional) plus or minus sign
- nonempty sequence of decimal digits optionally containing a decimal point character (defines significand)
- (optional) e or E followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
- binary floating point expression. It consists of the following parts:
- (optional) plus or minus sign
- 0x or 0X
- nonempty sequence of hexadecimal digits optionally containing a decimal point character (defines significand)
- (optional) p or P followed with optional minus or plus sign and nonempty sequence of hexadecimal digits (defines exponent)
- infinity expression. It consists of the following parts:
- (optional) plus or minus sign
- INF or INFINITY ignoring case
- not-a-number expression. It consists of the following parts:
- (optional) plus or minus sign
- NAN or NAN(char_sequence) ignoring case of the NAN part. char_sequence can only contain alphanumeric characters. The result is a quiet NaN floating point value.
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 integer to store the index of the first unconverted character |
[edit] Return value
The string converted to the specified floating point 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.
[edit] See also
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(C++11)
(C++11) (C++11) |
converts a string to an signed integer (function) |
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(C++11)
(C++11) |
converts a string to an unsigned integer (function) |