printf confusion

[Bhaarat Sharma]

i can't seem to get the hang of printf. how did you guys memorize all the combinations?

Also

int i2 = 12345;
System.out.printf(">%1$< \n", i2); //error at runtime

int i2 = 12345;
System.out.printf(">%1$d< \n", i2);//fine at runtime

...do we always need to have d in the end?

[Prasad Kharkar]

following are the characters those are required for outputting specific type of values
d for integers
b for booleans
s for strings
c for character and
f for float

and yes we have to give those character for respective values because the compiler gives error at runtime

[Michael Hilgert]

Yes, that's right.
First have a look to the easiest printf.
All what you need is a % and a letter described above.

int i2 = 12345;   
System.out.printf("%d", i2);

or

double d2 = 123.456;
System.out.printf("%f", d2); // float and double need a f

Then you can add other signs.

System.out.printf("%07f", d2); // leading 0 and a length of 7

Do you want to have less digits after the dot, use

System.out.printf("%07.2f", d2); // leading 0 and a length of 7

and so on
$1 : use the first parameter

[Frits Walraven]

You can check the API documentation:
Java5API
and choose the class java.io.PrintStream.printf(String format, Object... args)
If you have read that, go further on the format section: format string format
Regards,
Frits