| atof |
(String str) |
yoix.string |
| |
Returns the number obtained by converting
str
to a double.
atof
skips leading white space and then accepts an optional sign,
a string of digits that may include a decimal point,
and an optional signed integer exponent introduced by an
e
or
E.
atof
stops at the first unrecognized character and returns
0
when no number is found.
atof
also accepts the (currently case-sensitive) strings
NaN
and
Infinity,
which can be preceded by an optional sign, and converts them to
NaN,
POSITIVE_INFINITY,
or
NEGATIVE_INFINITY,
which are constants defined in
yoix.math.
| |
| Example: |
Put the simple option parsing program
import yoix.*.*;
double mag = 1.0;
Option opt;
int ch;
while ((ch = getopt(opt, global.argv, "m:")) != -1) {
switch (ch) {
case 'm':
mag = atof(opt.optarg);
break;
case '?':
fprintf(stderr, "Error: %s\n", opt.opterror);
exit(1);
}
}
printf("mag=%.1f\n", mag);
in a file named
atof.yx,
run the interpreter by typing,
yoix atof.yx -m12.3
and
mag=12.3
prints on standard output.
| | |
| Return: |
double
| | |
| See Also: |
atoi,
strtod,
strton
|
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Yoix is a registered trademark of AT&T Inc.
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