CODEWITHSUNDEEP
javado-while
maddie pattie c
maddie pattie c

Reputation: 11

Do - while loop with conditions using Char (Java)

So I'm working on this energy tree project for my computer programming class, I was trying to make a do-while loop that asked the user if they were a producer or consumer and if any other input was entered loop would start over. My code keeps getting the error 

"java.util.NoSuchElementException" on line 45

where it says 

char Type = ProducerOrConsumer.nextLine().toUpperCase().charAt(0);



        boolean isChoiceValid = false;

        do
        {
            PETCScanner.close();
            Scanner ProducerOrConsumer = new Scanner(System.in);

            System.out.println("Are you a Producer or a Consumer?\\\\n (P = Producer, C = Consumer");
            char Type = ProducerOrConsumer.nextLine().toUpperCase().charAt(0);
            if (Type == 'P' || Type =='C')
            {


            }
            else 
                System.out.println("Sorry try Again");
            {

            }
            String Name = ProducerOrConsumer.nextLine().toUpperCase();

            System.out.println(Name);


        }while(isChoiceValid == (true));
        System.out.println("You're Done!");


    }

Upvotes: 1

Views: 1161

Answers (3)

OneCricketeer
OneCricketeer

Reputation: 191701

It seems you are closing a Scanner, which closes all attached resources. When trying to read again, you have "no such element" to read.

You only need one scanner per application, there is no need to re-create one, too. 

Scanner sc = new Scanner(System.in);
boolean isChoiceValid = false;
do {
     System.out.println("Are you a Producer or a Consumer?\\\\n (P = Producer, C = Consumer");
    char type = sc.nextLine().toUpperCase().charAt(0);
    if (type == 'P' || type =='C') {
        boolean isChoiceValid = true;
    } else {
        System.out.println("Sorry try Again");
        isValidChoice = false;  // if you want
        continue;
    }
    if (sc.hasNextLine()) {
        String name = sc.nextLine().toUpperCase();
        System.out.println(name);
    }
} while(!isChoiceValid);
System.out.println("You're Done!");

Upvotes: 1

Scratte
Scratte

Reputation: 3166

After removing PETCScanner.close(); I ran your code, and I don't get any errors. I get this:

Are you a Producer or a Consumer?\\n (P = Producer, C = Consumer
Neither
Sorry try Again
O
O
You're Done!

Upvotes: 0

turong
turong

Reputation: 1622

I saw that the exception was thrown from the calling ProducerOrConsumer.nextLine().

There was no element found as the result == null. You can have a look more detailed in the java.util.Scanner.nextLine()

public String nextLine() {
        ...
        if (result == null)
            throw new NoSuchElementException("No line found");
        ...
        if (result == null)
            throw new NoSuchElementException();
        ...
}

Best,

Upvotes: 0

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