double strtod( const char *str, char **endptr )
- prototype in string.h - converts string str to a double value - stops reading at tfirst character that cannot be interpreted as part of a double value, returning in *endptr - str must have format: [ws][sn][ddd][.][ddd][fmt[sn]ddd] where [ws] = optional whitespace [sn] = optional sign (+-) [ddd] = optional digits [fmt] = option e or E [.] = optional decimal point