| fprintf |
(Stream stream, String format [, Object obj1, ..., Object objN]) |
yoix.stdio |
| |
Converts objects to strings under the control of a
format
specification, writes the results to
stream,
and returns the number of characters written, or
-1
if there was an error.
The
format
string consists of zero or more of the following components:
-
ordinary characters that are copied directly to the output
stream.
-
conversion specifications that determine how arguments are converted to strings.
There should be general agreement between the type of
a conversion specification and the corresponding argument.
Each format conversion has the general form,
%[ flag ][ width ][. precision ]specification
where the square brackets indicate optional elements and:
-
flag
is one or more of:
| - |
indicating left-justification.
| | + |
indicating right-justification.
| | (sp) |
indicating right-justify and pad with spaces.
| | 0 |
indicating right-justify and pad with zeros.
| | # |
indicating lead octals with a "0" and hexadecimals with a "0x".
| | ' |
indicating locale specific grouping and decimal point presentation for the default
Locale.
|
-
width
indicates the minimum field width.
-
precision
indicates the maximum field width for strings or, for numbers,
the decimal precision.
-
specification
is one of:
| c |
takes the integer portion of a number and interprets it as a Unicode
character.
| | d |
takes only the integer portion of a number.
| | e or E |
expresses a number using base-10 exponential notation (with a "e" or "E"
being used to indicate where the exponent begins).
| | f |
expresses the real portion of a number using decimal notation.
| | g or G |
provides generic formatting for numbers: for real number, formatting is
like "f" or "e" formatting, as appropriate ("f" or "E" if "G" is specified)
and, for integers, formatting is like d.
| | o |
expresses the integer portion of a number in octal format.
| | O |
formats any object in the manner of the
toString
built-in and uses the
precision,
if supplied, to control the depth of the dump.
| | s or S |
for handling strings ("S" takes the whole string, nulls and all, while "s" stops at the first null).
| | x or X |
expresses the integer portion of a number in hexadecimal format
(with a "x" or "X"
being used to indicate whether the alphabetic digits should be lower-case or
upper-case respectively).
| | % |
just output a percent sign, no argument is converted and the entire
conversion specification must be just "%%".
|
Incidentally, the
strfmt
built-in, which is available in
yoix.string,
provides
fprintf
formatting capabilities without writing the output directly to a stream.
| |
| Example: |
The program,
import yoix.math.*;
import yoix.stdio.*;
int i = 65;
double x = 400 * atan(1);
String city[10] = "New York";
fprintf(stdout, "A: 1(%d) 2(%d) 3(%05d) 4(%-5d)\n", i, x, i, i);
fprintf(stdout, "B: 1(%c) 2(%o) 3(%x) 4(%#06x)\n", i, i, i, i);
fprintf(stdout, "C: 1(%f) 2(%e) 3(%5.3E) 4(%g)\n", x, x, x, x);
fprintf(stdout, "D: 1(%s) 2(%10.5s) 3(%S)\n", city, city, city);
prints
A: 1(65) 2(314) 3(00065) 4(65 )
B: 1(A) 2(101) 3(41) 4(0x0041)
C: 1(314.159265) 2(3.141593e+02) 3(3.142E+02) 4(314.15927)
D: 1(New York) 2( New Y) 3(New York\0\0)
on standard output (where
\0
is used to represent otherwise invisible null characters).
| | |
| Return: |
int
| | |
| See Also: |
fscanf,
printf,
scanf,
sprintf,
sscanf,
strfmt,
toString
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Yoix is a registered trademark of AT&T Inc.
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