Identifying Invalid input

I need a bit of code such as else if () that will allow my scanner to be identified as invalid, invalid inputs would be anything that is not and integer ranging from 2 to 10.

Steps;

1. First create a scanner object e.g Scanner sc = new Scanner(System.in)
2. Read the value from keyboard and store it into int varialbe e.g int value = sc.nextInt();
3. Now check if value is within the range or not?

if(value < 2 || value > 10)
{
// then this in not in range(Invalid)
}
else
{
//within the range(valid)
}

Quote:

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Originally Posted by Amok

Steps;

1. First create a scanner object e.g Scanner sc = new Scanner(System.in)
2. Read the value from keyboard and store it into int varialbe e.g int value = sc.nextInt();
3. Now check if value is within the range or not?

if(value < 2 || value > 10)
{
// then this in not in range(Invalid)
}
else
{
//within the range(valid)
}

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Fine; now suppose I type "foobar"; is that in range? Guess what would happen. Making your code monkey (me) proof takes a bit more ...

kind regards,

Jos

@JosAH, we can always put int value = sc.nextInt(); within try/catch block. If its a String then we can catch it within catch block and print a message saying its not in a range. I m sorry if i am wrong. There are many way we can do it and its a programmer choice how to approach to it, thats why i didn't mentioned it.

Quote:

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Originally Posted by Amok

@JosAH, we can always put int value = sc.nextInt(); within try/catch block. If its a String then we can catch it within catch block and print a message saying its not in a range. I m sorry if i am wrong. There are many way we can do it and its a programmer choice how to approach to it, thats why i didn't mentioned it.

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Yep, but keep in mind that if the user didn't type any digits, the nextInt() method won't read anything, so a next call to the nextInt() method chews on those same none-digits again; you have to get rid of them (in the catch-clause). Making input handling really monkey proof takes a bit more than try-catching the conflicting input ...

kind regards,

Jos

Thanks alot

So what should I do? lol

Quote:

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Originally Posted by JosAH

Yep, but keep in mind that if the user didn't type any digits, the nextInt() method won't read anything, so a next call to the nextInt() method chews on those same none-digits again; you have to get rid of them (in the catch-clause). Making input handling really monkey proof takes a bit more than try-catching the conflicting input ...

kind regards,

Jos

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Just remember that once a programmer makes his software "idiot proof", someone comes along with a better idiot. :P:

Quote:

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Originally Posted by Keith Jackson

Just remember that once a programmer makes his software "idiot proof", someone comes along with a better idiot. :P:

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Yes, isn't life cruel?

kind regards,

Jos