Difference between revisions of "cpp/string/basic string/stof"
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float stof( const std::string& str, size_t *pos = 0 ); | float stof( const std::string& str, size_t *pos = 0 ); | ||
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double stod( const std::string& str, size_t *pos = 0 ); | double stod( const std::string& str, size_t *pos = 0 ); | ||
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long double stold( const std::string& str, size_t *pos = 0 ); | long double stold( const std::string& str, size_t *pos = 0 ); | ||
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Revision as of 14:54, 24 December 2011
Template:cpp/string/basic string/sidebar Template:ddcl list begin <tr class="t-dsc-header">
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<td ><td > (1) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">
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<td ><td > (3) </td> <td > (since C++11) </td> </tr> Template:ddcl list end
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 a 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 decimal-point character (as determined by the current C locale) (defines significand)
- (optional)
eorEfollowed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent to base 10)
- hexadecimal floating-point expression. It consists of the following parts:
- (optional) plus or minus sign
-
0xor0X - nonempty sequence of hexadecimal digits optionally containing a decimal-point character (as determined by the current C locale) (defines significand)
- (optional)
porPfollowed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent to base 2)
- infinity expression. It consists of the following parts:
- (optional) plus or minus sign
-
INForINFINITYignoring case
- not-a-number expression. It consists of the following parts:
- (optional) plus or minus sign
-
NANorNAN(char_sequence)ignoring case of theNANpart. char_sequence can only contain digits, Latin letters, and underscores. The result is a quiet NaN floating-point value.
- any other expression that may be accepted by the currently installed C locale
The index of the first unconverted character is stored in pos. If Template:cpp is passed as pos, it is ignored.
Contents |
Parameters
| str | - | the string to convert |
| pos | - | address of integer to store the index of the first unconverted character |
Return value
The string converted to the specified floating point type.
Exceptions
Template:cpp if no conversion could be performed
Template:cpp if the converted value would fall out of the range of the result type.
