cant find error source from scanner char input

Question

//opens/closes scanner, uppercases user input, and returns it as an int
public static int seeker() {
Scanner kb = new Scanner (System.in);
char guess = Character.toUpperCase(kb.next().charAt(0));

kb.close();
return guess;
}

I keep getting these messages:
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)

helppp!!! <3

Answer 1

Jeff Well, the idea is that you shouldn't be taking input in the function. If possible, create a Scanner object in the main function, reuse the object and close it before the program ends. This way, you solve your problems and also avoid creating new Scanner objects every time the function is called.

Answer 2

Each time your function is entered you allocate a new scanner. Only the first time has access to the input.

Answer 3

My guess is your input is the issue. Link your code by hitting the circle/plus icon so we can run the same code and gives us the input you entered at the prompt.

However, if you allocated two Scanner classes, the second will not get any input.

Answer 4

Jeff Have you tried not closing the Scanner object? As I'm pretty sure that is the case, with the input source being closed along with the Scanner.

Answer 5

The function as it is presented here works just fine. I wasn't able to recreate the errors with just this:

import java.util.Scanner;

public class Program
{
public static int seeker() {
Scanner kb = new Scanner (System.in);
char guess = Character.toUpperCase(kb.next().charAt(0));

kb.close();
return guess;
}
public static void main(String[] args) {
System.out.print(seeker());
}
}

However, it is possible that you continued to use scanners after you closed the scanner object. Closing the scanner object will also close System.in.

https://stackoverflow.com/questions/13042008/java-util-nosuchelementexception-scanner-reading-user-input

Answer 6

So here's the full code, its basically a random letter generator that checks against a char input :

import java.util.Random;
import java.util.Scanner;

public class Jeff_McCann_CIS106_HYB1_GuessALetter {

//returns random uppercase char
public static char pickLetter() {
Random rnd = new Random();
char letter = Character.toUpperCase((char) (rnd.nextInt(26) + 'a'));

return letter;
}

//opens/closes scanner, uppercases user input, and returns it as an int
public static int seeker() {
Scanner kb = new Scanner (System.in);
char guess = Character.toUpperCase(kb.next().charAt(0));

kb.close();
return guess;
}

public static void main(String[] args) {
char mystery = pickLetter(); //random picked constant variable
boolean found = false;

System.out.println("Let's play guess the letter!");

do {
System.out.println();
System.out.print("Enter a letter (upper or lower case): ");
int x = mystery; //A=65-Z=90
int y = seeker();

if (x == y) {
System.out.println("You guessed it!");
System.out.println("The letter was " + mystery);
found = true;
}
else if (x < y){
System.out.println("Your letter comes before the secret letter");
}
else {
System.out.println("Your letter comes after the secret letter");
}
}while(!found);

}

}

Answer 7

The errors are resolved by leaving the scanner unclosed; but i hate seeing that flag and I know its bad practice? where should I close it?