Question

I encountered an error when executing my program.

I execute my program and fed data in an input file.

Contents of the input file

LIMIT
2
ADD 30 60
MUL -60 60

I got an exception error as follows.

Exception in thread "main" java.util.NoSuchElementException
        at java.util.Scanner.throwFor(Scanner.java:907)
        at java.util.Scanner.next(Scanner.java:1530)
        at java.util.Scanner.nextInt(Scanner.java:2160)
        at java.util.Scanner.nextInt(Scanner.java:2119)
        at Test.doLimit(Test.java:41)
        at Test.checkResult(Test.java:24)
        at Test.main(Test.java:15)

I googled and I believed that String input = sc.next(); inside the for loop should be causing the error.
May I know how to resolve this error?

My code is as attached below.

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String input = sc.nextLine();
    checkResult(input);
}


public static void checkResult(String input)
{
    if(input.equals("LIMIT"))
    {
        //do stuff
        doLimit();
    }
    else if(input.equals("SENT"))
    {
        //do stuff

    }
    else
    {
        //do stuff

    }
}
public static void doLimit()
{
    Scanner sc = new Scanner(System.in);
    int numOfInput = sc.nextInt();
    int x,y;
    for(int i = 0; i < numOfInput; i++)
    {
        String input = sc.next();
        x = sc.nextInt();
        y = sc.nextInt();

        if(input.equals("ADD"))
        {
            //add

        }
        else if(input.equals("SUB"))
        {
            //sub

        }
        else
        {
            //multiple

        }
    }
}

Answer 1

You should check if there is more input. You can see in the stack trace that nextInt is involved and if you look at the SDK you would see that this exception is thrown when

input is exausted.

anyway you problem is here :

int numOfInput = sc.nextInt();

so make sure you have valid input before asking for it :

if (sc.hasNextInt()) {
  .
  .
  .
}