Java Reference
In-Depth Information
Although it is legal to use the escape sequence
\n
to indicate a line break in a format
string, it is preferable to use
%n
. Exactly what happens when a
\n
is output can be sys-
tem dependent, whereas
%n
should always mean a simple new line on any system. So
our last line of code would be a little more robust if rewritten using
%n
as follows:
%n
System.out.printf("$%6.2f for each %s.%n", price, name);
Many of the details we have discussed about
printf
are illustrated in the program
given in Display 2.2.
TIP: Formatting Money Amounts with
printf
A good format specifier for outputting an amount of money stored as a value of type
double
(or other floating-point value) is
%.2f
. It says to include exactly two digits
after the decimal point and to use the smallest field width that the value will fit into.
For example,
double
price = 19.99;
System.out.printf("The price is $%.2f each.", price);
produces the output:
■
The price is $19.99 each.
Display 2.2
The
printf
Method
(part 1 of 2)
1
public class
PrintfDemo
2{
3
public static void
main(String[] args)
4
{
5
String aString = "abc";
6
System.out.println("String output:");
7
System.out.println("START1234567890");
8
System.out.printf("START%sEND %n", aString);
9
System.out.printf("START%4sEND %n", aString);
10
System.out.printf("START%2sEND %n", aString);
11
System.out.println();
12
char
oneChracter = 'Z';
13
System.out.println("Character output:");
14
System.out.println("START1234567890");
15
System.out.printf("START%cEND %n", oneCharacter);
16
System.out.printf("START%4cEND %n", oneCharacter);
17
System.out.println();
(continued)
