dividebyzeroexceptiondemo.java

关于牛奶和饼干的分配问题,把饼干的数量和牛奶的数量平均分配.

import java.util.*;

public class DivideByZeroExceptionDemo
{
    private int numerator;
    private int denominator;
    private double quotient;

    public static void main(String[] args)
    {
        DivideByZeroExceptionDemo oneTime =
                              new DivideByZeroExceptionDemo( );
        oneTime.doIt( );
    }

    public void doIt( )
    {
        try
        {
            System.out.println("Enter numerator:");
            Scanner keyboard = new Scanner(System.in);
            numerator = keyboard.nextInt( );
            System.out.println("Enter denominator:");
            denominator = keyboard.nextInt( );

            if (denominator == 0)
                throw new DivideByZeroException( );

            quotient = numerator/(double)denominator;
            System.out.println(numerator + "/"
                                 + denominator
                                 + " = " + quotient);
        }
        catch(DivideByZeroException e)
        {
            System.out.println(e.getMessage( ));
            secondChance( );
        }

        System.out.println("End of Program.");
    }

    public void secondChance( )
    {
        System.out.println("Try again:");
        System.out.println("Enter numerator:");
        Scanner keyboard = new Scanner(System.in);

        numerator = keyboard.nextInt( );
        System.out.println("Enter denominator:");
        System.out.println("Be sure the denominator is not zero.");
        denominator = keyboard.nextInt( );

        if (denominator == 0)
        {
            System.out.println("I cannot do division by zero.");
            System.out.println("Since I cannot do what you want,");
            System.out.println("the program will now end.");
            System.exit(0);
        }

        quotient = ((double)numerator)/denominator;
        System.out.println(numerator + "/"
                                     + denominator
                                     + " = " + quotient);
    }
}