Java回文，方法和抽象类？

Question

I'm stuck on an assignment, largely due to an extreme lack of examples or even relevant diagrams from my textbook and class material.

The reason I structured the program the way I did is because I'm required to use 4 methods: a main method that executes all the other methods, a retrieve input method, a check method, and a display method. I love to hear about best practices, but I'm forced to code like this.

My main problem is the abstract classes I have. Any variables I write in one method won't be resolvable in another, I don't know how to make the variables global.

secondly, the code does not compile, the example I've found doesn't have a classic main, i don't really know how to make main implement methods, or make the compiler happy with abstraction.

also no clue on how to take my boolean result and use that to display the results in the display method. yes its asinine, I'd rather just do it in the check method.

all i know for sue is that my "logic" so far works. i think. any help to point me in the right direction would be very much appreciated. if thee is a way to do this without abstract classes i'd love to hear it, i think the abstraction is unnecessary.

well here's my monster so far:

import javax.swing.JOptionPane;

interface Palindrome {

void retrieveInput(String[] args);
boolean Check(String s);
void display();

}

abstract class Sub_Palindrome  implements Palindrome {

public void retrieveInput(String[] args)
{
    String Uinput;
    int number1;
    int digit1; // first digit
    int digit2; // second digit
    int digit3;
    int digit4; // fourth digit
    int digit5; // fifth digit
    Uinput = JOptionPane.showInputDialog("Enter A 5 Digit Integer");

    try { //Sanitize user input, make sure input entered is a number
        number1 = Integer.parseInt(Uinput);
    } catch (NumberFormatException String) {
        JOptionPane.showMessageDialog(null, "Input invalid, please enter an integer",
                "///-D-A-T-A---E-R-R-O-R-\\\\\\", JOptionPane.ERROR_MESSAGE);
        return;
    }
    if (number1 < 10000 || number1 > 99999) { //Sanitize user input, make sure the given number is between 10000 and 99999
        JOptionPane.showMessageDialog(null, 
                "The number entered must be between 10000 and 99999",
                "///-D-A-T-A---E-R-R-O-R-\\\\\\", JOptionPane.ERROR_MESSAGE);
        return;
    }


}

public boolean Check(String s)
{ 
     digit1 = number / 10000;
     digit2 = number / 1000 % 10;
     digit3 = number % 1000 / 100 % 10; // is the third digit even necessary?
     digit4 = number % 10000 % 1000 % 100 / 10;
     digit5 = number % 10000 % 1000 % 100 % 10;

     if (digit1 == digit5 && digit2 == digit4)
         return true;
     else
         return false;

}   

public void display()
{

    //display output text based upon result from IsPalinDrome
    //after displaying result, start from the beginning and ask user to input data again

}

}

Answer 1

1. Move the variables outside methods and put directly in class scope
2. Writing main method is the first thing you learn in java. Look into your tutorial again
3. You can use a boolean variable boolean displayCheck = false; and set the same

And one question from my side: If your code doesn't compile what makes you feel that the logic is correct?