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/**
* A class for formatting numbers that follows printf
* conventions.
* Also implements C-like atoi and atof functions
* @version 1.01 15 Feb 1996
* @author Cay Horstmann
*/
package corejava;
import java.io.*;
public class
Format
{
/**
* Formats the number following printf conventions.
* Main limitation: Can only handle one format parameter
* at a time
* Use multiple Format objects to format more than one number
* @param s the format string following printf conventions
* The string has a prefix, a format code and a suffix.
* The prefix and suffix
* become part of the formatted output. The format code
* directs the
* formatting of the (single) parameter to be formatted.
* The code has the
* following structure
* <ul>
* <li> a % (required)
* <li> a modifier (optional)
* <dl>
* <dt> + <dd> forces display of + for positive numbers
* <dt> 0 <dd> show leading zeroes
* <dt> - <dd> align left in the field
* <dt> space <dd> prepend a space in front of positive
numbers
* <dt> # <dd> use "alternate" format. Add 0 or 0x
for octal
* or hexadecimal numbers. Don't suppress trailing
zeroes in
* general floating point format.
* </dl>
* <li> an integer denoting field width (optional)
* <li> a period followed by an integer denoting
* precision (optional)
* <li> a format descriptor (required)
* <dl>
* <dt>f <dd> floating point number in fixed format
* <dt>e, E <dd> floating point number in exponential
notation
* (scientific format). The E format results in an
uppercase
* E for the exponent (1.14130E+003), the e format
in a
* lowercase e.
* <dt>g, G <dd> floating point number in general
format
* (fixed format for small numbers, exponential format
for
* large numbers). Trailing zeroes are suppressed.
The G
* format results in an uppercase E for the exponent
(if any),
* the g format in a lowercase e.
* <dt>d, i <dd> integer in decimal
* <dt>x <dd> integer in hexadecimal
* <dt>o <dd> integer in octal
* <dt>s <dd> string
* <dt>c <dd> character
* </dl>
* </ul>
* @exception IllegalArgumentException if bad format
*/
public Format(String s)
{
[..See
the source code
for details of
how formatting is performed..]
/**
* prints a formatted number following printf conventions
* @param s a PrintStream
* @param fmt the format string
* @param x the double to print
*/
public static void print(java.io.PrintStream
s,
String fmt, double x)
{ s.print(new Format(fmt).form(x));
}
/**
* prints a formatted number following printf conventions
* @param s a PrintStream
* @param fmt the format string
* @param x the long to print
*/
public static void print(java.io.PrintStream
s,
String fmt, long x)
{ s.print(new Format(fmt).form(x));
}
/**
* prints a formatted number following printf conventions
* @param s a PrintStream
* @param fmt the format string
* @param x the character to
*/
public static void print(java.io.PrintStream
s,
String fmt, char x)
{ s.print(new Format(fmt).form(x));
}
/**
* prints a formatted number following printf conventions
* @param s a PrintStream, fmt the format string
* @param x a string that represents the digits to print
*/
public static void print(java.io.PrintStream
s,
String fmt, String x)
{ s.print(new Format(fmt).form(x));
}
//
The following print() methods with StringWriter streams
// was added to allow for formatted output to a String object.
/**
* prints a formatted number following printf conventions
* @param s a StringWriter
* @param fmt the format string
* @param x the double to print
*/
public static void print(java.io.StringWriter
s,
String
fmt, double x)
{ s.write(new
Format(fmt).form(x));
}
/**
* prints a formatted number following printf conventions
* @param s a StringWriter
* @param fmt the format string
* @param x the long to print
*/
public static void print(java.io.StringWriter
s,
String fmt, long x)
{ s.write(new
Format(fmt).form(x));
}
/**
* prints a formatted number following printf conventions
* @param s a StringWriter
* @param fmt the format string
* @param x the character to
*/
public static void print(java.io.StringWriter
s,
String fmt, char x)
{ s.write(new
Format(fmt).form(x));
}
/**
* prints a formatted number following printf conventions
* @param s a StringWriter, fmt the format string
* @param x a string that represents the digits to print
*/
public static void print(java.io.StringWriter
s,
String fmt, String x)
{ s.write(new
Format(fmt).form(x));
}
[....more
code....]
/**
* a test stub for the format class
*/
public static void main(String[] a)
{ double x = 1.23456789012;
double y = 123;
double z = 1.2345e30;
double w = 1.02;
double u = 1.234e-5;
int d = 0xCAFE;
Format.print(System.out, "x = |%f|\n",
x);
Format.print(System.out, "u = |%20f|\n",
u);
Format.print(System.out, "x = |%
.5f|\n", x);
Format.print(System.out, "w = |%20.5f|\n",
w);
Format.print(System.out, "x = |%020.5f|\n",
x);
Format.print(System.out, "x = |%+20.5f|\n",
x);
Format.print(System.out, "x = |%+020.5f|\n",
x);
Format.print(System.out, "x = |%
020.5f|\n", x);
Format.print(System.out, "y = |%#+20.5f|\n",
y);
Format.print(System.out, "y = |%-+20.5f|\n",
y);
Format.print(System.out, "z = |%20.5f|\n",
z);
Format.print(System.out, "x = |%e|\n",
x);
Format.print(System.out, "u = |%20e|\n",
u);
Format.print(System.out, "x = |%
.5e|\n", x);
Format.print(System.out, "w = |%20.5e|\n",
w);
Format.print(System.out, "x = |%020.5e|\n",
x);
Format.print(System.out, "x = |%+20.5e|\n",
x);
Format.print(System.out, "x = |%+020.5e|\n",
x);
Format.print(System.out, "x = |%
020.5e|\n", x);
Format.print(System.out, "y = |%#+20.5e|\n",
y);
Format.print(System.out, "y = |%-+20.5e|\n",
y);
Format.print(System.out, "x = |%g|\n",
x);
Format.print(System.out, "z = |%g|\n",
z);
Format.print(System.out, "w = |%g|\n",
w);
Format.print(System.out, "u = |%g|\n",
u);
Format.print(System.out, "y = |%.2g|\n",
y);
Format.print(System.out, "y = |%#.2g|\n",
y);
Format.print(System.out, "d = |%d|\n", d);
Format.print(System.out, "d = |%20d|\n",
d);
Format.print(System.out, "d = |%020d|\n",
d);
Format.print(System.out, "d = |%+20d|\n",
d);
Format.print(System.out, "d = |%
020d|\n", d);
Format.print(System.out, "d = |%-20d|\n",
d);
Format.print(System.out, "d = |%20.8d|\n",
d);
Format.print(System.out, "d = |%x|\n",
d);
Format.print(System.out, "d = |%20X|\n",
d);
Format.print(System.out, "d = |%#20x|\n",
d);
Format.print(System.out, "d = |%020X|\n",
d);
Format.print(System.out, "d = |%20.8x|\n",
d);
Format.print(System.out, "d = |%o|\n",
d);
Format.print(System.out, "d = |%020o|\n",
d);
Format.print(System.out, "d = |%#20o|\n",
d);
Format.print(System.out, "d = |%#020o|\n",
d);
Format.print(System.out, "d = |%20.12o|\n",
d);
Format.print(System.out, "s = |%-20s|\n",
"Hello");
Format.print(System.out, "s = |%-20c|\n",
'!');
}
}
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