Read number as string sequence and convert first and last to an Integer

Question

I'm new to programming and I've just started learning Java.
I want to do a program that's

asks the user to enter a string that contains a sequence of numbers and then
takes the first and the last numbers of that sequence and
check if these numbers are an odd or even

Based on that information it will do certain things.

Here's my code:

public static void main(String[] args) {
    Scanner kb = new Scanner(System.in);
    String n = kb.nextLine();
    Integer x = Integer.valueOf(n.charAt(n.length() - 1));
    Integer y = Integer.valueOf(n.charAt(0));
    String out;
    if (y % 2 == 0 && x % 2 == 0) {
        out = "$" + n.substring(1, n.length() - 1) + "$";
    } else if (y % 2 > 0 && x % 2 > 0) {
        out = "X" + n.substring(1, n.length() - 1) + "X";
    } else if (x == 0); {
        out = n.substring(0, n.length() - 1) + "#";
    }
    System.out.println(out);
}

I'm not sure what's the problem. I think its about those two lines

Integer x = Integer.valueOf(n.charAt(n.length()-1));
Integer y = Integer.valueOf(n.charAt(0));

The output value is different than the one in the input..

absolutely, thank you very much!, sorry for the late response though.. — Aifa, Oct 21 '18 at 12:51

wp78de · Accepted Answer · 2018-10-12T04:27:08.763

The Scanner code can be improve and there is indeed a problem with your conversion. Your code gets the ASCII value of those symbols. Try it like this:

public static void main (String[] args) throws java.lang.Exception
{
    Scanner console = new Scanner(System.in);

    while (console.hasNextLine()) {
        String n = console.nextLine();
        Integer x = Integer.parseInt(n.substring(n.length()-1));
        //System.out.println(x);
        Integer y = Integer.parseInt(n.substring(0, 1));
        //System.out.println(y);
        String out;
        if (y % 2 == 0 && x % 2 == 0)
        {
            out = "$"+n.substring(1, n.length()-1)+"$";
        }
        else if (y % 2 > 0 && x % 2 > 0) {
            out = "X" +n.substring(1, n.length()-1) + "X";
        }
        else if (x == 0); 
        {
        out = n.substring(0, n.length()-1)+ "#";
        }
        System.out.println(out);
    }
}

Online Demo

I've used substring()/parseInt() but there are many ways to convert a string or char to an Integer.

Read number as string sequence and convert first and last to an Integer

1 Answers1