how to clear input buffer in java

Question

For avoiding any unwanted character which has been entered in console like \n

we use nextInt() or nextLine() etc.

But in these cases actually the control is going a step ahead leaving the unwanted string or something like this. But I want to delete or flush out the memory of buffer in which other unwanted data is taken by the system. For example -->

Scanner scan=new Scanner(System.in);
scan.nextInt();
scan.nextline();//this statement will be skipped

because the system is taking \n as a line next to the integer given as input. In this case without using scan.nextLine() I want to simply clear/flush out the buffer memory where the \n was stored. Now please tell me how to delete the input buffer memory in java

Thank you. :)

control is not waiting for taking input a line or anything, it is skipping. — ANUPAM, Jun 22 '15 at 17:06
@ANUPAMCHANDA and that's precisely what you want: ignore the end of the line after the integer, no? If not, what do you want? — JB Nizet, Jun 22 '15 at 17:15
Yes. I want to ignore the end of the line after integer no, but by clearing the input buffer not by the way to push the control forward ignoring the end of line. — ANUPAM, Jun 23 '15 at 01:44

Pieter12345 · Answer 1 · 2015-06-22T17:20:15.170

2

You can use this to clear all existing data in the buffer:

while(sc.hasNext()) {
    sc.next();
}

If you are only doing this to remove the newline (\n) characters from the input, you can use:

while(sc.hasNext("\n")) {
    sc.next();
}

If the goal is to only read integers and skip any other characters, this would work:

while(sc.hasNext() && !sc.hasNextInt()) {
    sc.next();
}

edited Jun 22 '15 at 17:20

answered Jun 22 '15 at 17:02

Pieter12345

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@ANUPAMCHANDA Did this answer solve your question? If it did not, please explain your question more clear. Otherwise, mark the question as answered. – Pieter12345 Jun 22 '15 at 18:49

score 0 · Answer 2 · edited Jan 02 '23 at 10:15

0

you can simply use one more scan.nextLine() before taking the string as input.

Scanner scan = new Scanner(System.in);
int x = scan.nextInt();
scan.nextLine();  // clears the input buffer
String s = scan.nextLine();  // this statement won't get skip

Reference : the solution to this hackerrank question uses the same idea which I provided

edited Jan 02 '23 at 10:15

nakhodkin

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answered Jan 01 '23 at 12:32

Kanisht Agarwal

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how to clear input buffer in java

2 Answers2

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