#variable not getting assigned input from userInput

1 messages · Page 1 of 1 (latest)

serene quartzBOT
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<@&987246399047479336> please have a look, thanks.

pliant fjord
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please share the entire code

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the code u showed would work

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so the issue must be elsewhere

modest plank
pliant fjord
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i suspect a particular issue with scanner though

fathom chasm
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My money is on you having a nextInt() before the nextString().

serene quartzBOT
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Mixing any nextXXX method with nextLine from the Scanner class for user input, will not ask you for input again but instead result in an empty line read by nextLine.

To prevent this, when reading user input, always only use nextLine. If you need an int, do

int value = Integer.parseInt(scanner.nextLine());

instead of using nextInt.

Assume the following:

Scanner scanner = new Scanner(System.in);

System.out.println("Enter your age:");
int age = scanner.nextInt();
System.out.println("Enter your name:");
String name = scanner.nextLine();

System.out.println("Hello " + name + ", you are " + age + " years old");

When executing this code, you will be asked to enter an age, suppose you enter 20.
However, the code will not ask you to actually input a name and the output will be:

Hello , you are 20 years old.

The reason why is that when you hit the enter button, your actual input is

20\n

and not just 20. A call to nextInt will now consume the 20 and leave the newline symbol \n in the internal input buffer of System.in. The call to nextLine will now not lead to a new input, since there is still unread input left in System.in. So it will read the \n, leading to an empty input.

So every user input is not only a number, but a full line. As such, it makes much more sense to also use nextLine(), even if reading just an age. The corrected code which works as intended is:

Scanner scanner = new Scanner(System.in);

System.out.println("Enter your age:");
// Now nextLine, not nextInt anymore
int age = Integer.parseInt(scanner.nextLine());
System.out.println("Enter your name:");
String name = scanner.nextLine();

System.out.println("Hello " + name + ", you are " + age + " years old");

The nextXXX methods, such as nextInt can be useful when reading multi-input from a single line. For example when you enter 20 John in a single line.

simon_verhoeven • used /tag id: scanner ·
pliant fjord
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yeah. its most likely that

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replace all ur nextXXX calls as the bot explains

modest plank
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I see. So, no mixing is allowed. Ill give that a go, thank you both.

pliant fjord
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well, techncially its possible

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but then u have to do it right

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which u attempted here

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but later u didnt

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and in line 107 it shouldnt be there either

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anyways, the easiest way is to not mix them

modest plank
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I see! Thank you very much 🙂

serene quartzBOT
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Closed the thread.