Declaration:
double atof(const char * str);
The string pointed to by the argument str
is converted to a floating-point number (type double ).
Any initial whitespace characters are skipped (space, tab,
carriage return, new line, vertical tab, or formfeed). The
number may consist of an optional sign, a string of digits with
an optional decimal character, and an optional e
or E followed by a optionally signed
exponent. Conversion stops when the first unrecognized character
is reached.
On success the converted number is returned. If no conversion
can be made, zero is returned. If the value is out of range of
the type double, then HUGE_VAL is returned
with the appropriate sign and ERANGE is
stored in the variable errno . If the value
is too small to be returned in the type double ,
then zero is returned and ERANGE is stored
in the variable errno . |