std::atof
std::atof
| Defined in header | | |
|---|---|---|
| double atof( const char *str | | |
Interprets a floating point value in a byte string pointed to by 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:
Parameters
| str | - | pointer to the null-terminated byte string to be interpreted |
|---|
Return value
double value corresponding to the contents of str on success. If the converted value falls out of range of the return type, the return value is undefined. If no conversion can be performed, 0.0 is returned.
Example
#include <cstdlib>
#include <iostream>
int main()
{
std::cout << std::atof("0.0000000123") << "\n"
<< std::atof("0.012") << "\n"
<< std::atof("15e16") << "\n"
<< std::atof("-0x1afp-2") << "\n"
<< std::atof("inF") << "\n"
<< std::atof("Nan") << "\n";
}
Output:
1.23e-08
0.012
1.5e+17
-107.75
inf
nan
See also
| strtofstrtodstrtold | converts a byte string to a floating point value (function) |
|---|
| C documentation for atof |
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