What is the use of formfeed and backspace escape strings in Java?

Question

Is there any practical usage for \r and \b in Java? Could someone give an example where it's used?

Well, when you need to output/save those characters, it's pretty handy don't you think? — Mat, Sep 11 '11 at 13:18
The question is not clear. The title references formfeed and backspace but the question references carriage return and backspace. — Douglas Held, Jun 19 '18 at 11:22

score 15 · Answer 1 · edited Feb 27 '15 at 09:06

15

Formfeed escape is \f, not \r. The former is useful for clearing the screen in a console, whilst the second is useful for progress displays (as stated by aioobe).

\b can be used in progress displays also, for example, on a ICMP Ping, you could display a dot when a ping is sent and a \b when it is received to indicate the amount of packet loss.

edited Feb 27 '15 at 09:06

nbro

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answered Sep 11 '11 at 13:27

squidge

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score 7 · Accepted Answer · answered Sep 11 '11 at 13:20

7

I usually use \r together with System.out.print when printing some progress percentage.

Try running this in your terminal:

class Test {
    public static void main(String[] args) throws InterruptedException {
        for (int i = 0; i < 100; i++) {
            System.out.print("Progress: " + i + " %\r");
            Thread.sleep(100);
        }
    }
}

answered Sep 11 '11 at 13:20

aioobe

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If I use \n instead of \r , it gives me the same results , what's the difference between two ? I guess \r is obsolete now. – Praveen Kumar Dec 08 '15 at 06:15
2

See [this q/a](http://stackoverflow.com/questions/1761051/difference-between-n-and-r). – aioobe Dec 08 '15 at 07:38

score 6 · Answer 3 · edited Feb 26 '18 at 12:02

6

Form feed is \f and \r is carriage return. \f is used for printing characters after it from new line starting just below previous character.

System.out.println("This is before\fNow new line");
System.out.println("TEXTBEFORE\rOverlap");
System.out.println("12\b3");

Output:

This is before
          Now new line
OverlapORE
13

edited Feb 26 '18 at 12:02

nkr

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answered Feb 26 '18 at 09:32

Rohan Gupta

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I like this answer but you did not explain the bell character. – Douglas Held Jun 05 '18 at 20:08
what the bell character has got to do here? – Rohan Gupta Jun 18 '18 at 14:34
Never mind, \b is backspace. I was confusing \b with \a – Douglas Held Jun 19 '18 at 11:20

score 3 · Answer 4 · answered Oct 20 '14 at 17:31

3

Form feed is a page-breaking ASCII control character. It forces the printer to eject the current page and to continue printing at the top of another. Often, it will also cause a carriage return. For further details click here

answered Oct 20 '14 at 17:31

Dillshad Rana

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What is the use of formfeed and backspace escape strings in Java?

4 Answers4