The reason it is necessary here is because of what happens when the input fails.
For example, try removing the input.nextLine()
part, run the program again, and when it asks for input, enter abc
and press Return
The result will be an infinite loop. Why?
Because nextInt()
will try to read the incoming input. It will see that this input is not an integer, and will throw the exception. However, the input is not cleared. It will still be abc
in the buffer. So going back to the loop will cause it to try parsing the same abc
over and over.
Using nextLine()
will clear the buffer, so that the next input you read after an error is going to be the fresh input that's after the bad line you have entered.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…