CIS 270—Application Development II

Chapter 28—Formatted Output

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23.1 Introduction Method printf formats and outputs data to

the standard output stream—_____________. Class Formatter does likewise to a specified

destination, such as a string or a file output stream.

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28.2 Streams A stream is a sequence of _______. For input, streams flow from a device to main

memory. For output, streams flow from main memory to

a device. Three automatic Java streams:

System.in—connected to the keyboard System.out—connected to the screen System.err—connected to the screen, for error

messages

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28.3 Formatting Output with printf

printf( format-string, argument-list ); format-string describes the output format

can contain fixed text and format ___________ a format specifier, such as f, is a placeholder for a

value a format specifier begins with % and is followed by a

conversion character, such as %f optional formatting information is specified between

the % and the conversion character, such as %.2f The argument-list contains literals or _________

that correspond in number and type to the conversion characters in the format-string.

The argument index (such as 1$) can specify argument to which formatting will apply: %1$.2f

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28.4 Printing Integers An integer is a + or – whole number with no

decimal point. Integral conversion characters

d for decimal (base 10) integers (e.g., 26) o for _______ (base 8) integers (e.g., 26 32) x or X for hexidecimal (base 16) integers (e.g. 26

1A) The printf method

Format: printf( format-string, argument-list ); Example:

int aNumber = 26; System.out.printf( “%d\n”, aNumber);

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28.5 Printing Floating-Point Numbers

A floating-point value contains a decimal point. Floating-point conversion characters

e or E for ____________ notation f for for floating-point, decimal format g or G for floating-point or exponential format

depending on the magnitude of the value (e for <10-3 or >107)

a or A for floating-point in hexidecimal format Examples

System.out.printf( “%e\n”, 12345678.9); Result: 1.2345678e+07 System.out.printf( “%f\n”, 12345678.9); Result: 12345678.900000

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28.6 Printing Strings and Characters

Character and string conversion characters c or C for characters (lower and upper case,

respectively) s or S for strings (lower and upper case,

respectively) Using s can convert an _________ object to a

string. Formatting characters cannot convert a string

to a character.

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28.7 Printing Dates and Times 1

The conversion characters t or T can print dates and times.

The conversion ________ character specifies formats.

Examples: %tc for complete date and time %tF for year-month-date format %tr for hour:minute:second AM|PM format %tA for the full day of the week (e.g., Wednesday) %tp for morning or afternoon marker in lower case

(pm)

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28.7 Printing Dates and Times 2

Application for dates and times Calendar today = Calendar.getInstance(); System.out.printf(“%1$tA, %1$tB %1$td,

%1$tY\n”, today); Result: Wednesday, August 03, 2005

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28.9 Printing with Field Widths and Precision

An integer right of % is the maximum field width (+ for right justification, - for left justification)

A . to the right of %, followed by a positive integer, is the number of decimal places to be displayed.

Example: printf( “%9.3f”, 123.456789 ); Right justifies (+, implied) using a __________

field width of 9 with 3 decimal places. Result: 123.457

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28.10 Using Flags A flag is placed just to the right of the % Flags

- to left justify + to display a + for positive values and – for

negative values 0 to pad a field with leading zeros , to use the locale-specific thousands separator ( to enclose negative numbers in parentheses

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28.13 Class Formatter System.out.printf() sends output to the

standard output stream (screen). The class Formatter (in package ___________) allows sending formatted output to a specified destination.

Example Formatter formatter = new Formatter(); formatter.format(“%d = %#o = %#X, 10, 10, 10); JOptionPane.showMessageDialog(null, formatter.toString());

Also, String x = String.format (“%d = %#o = %#X, 10, 10, 10);