Authors:
Walter Savitch ,kenrick Mock
Chapter:
Exception Handling
Exercise:
Programming Projects
Question:2 | ISBN:9780132830317 | Edition: 5
Question
Here is a snippet of code that inputs two integers and divides them:
Scanner scan = new Scanner(System.in);
int n1, n2;
double r;
n1 = scan.nextInt();
n2 = scan.nextInt();
r = ( double) n1 / n2;
Place this code into a try-catch block with multiple catches so that different error messages are printed if we attempt to divide by zero or if the user enters textual data instead of integers ( java.util.InputMismatchException ). If either of these conditions occurs, then the program should loop back and let the user enter new data.
Answer
Program:
// DivisionByZeroException.java
public class DivisionByZeroException extends Exception
{
public DivisionByZeroException()
{
super("Division by zero!");
}
public DivisionByZeroException(String msg)
{
super(msg);
}
}
// ExceptionDemo.java
import java.util.Scanner;
import java.util.InputMismatchException;
public class ExceptionDemo
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
int n1, n2;
double r;
boolean solved = false;
while(!solved)
{
try
{
System.out.print("Please enter a value for n1: ");
n1 = scan.nextInt();
System.out.print("Please enter a value for n2: ");
n2 = scan.nextInt();
if(n2 == 0)
throw new DivisionByZeroException();
r = (double) n1 / n2;
System.out.println("Result: "
+ n1 + "/" + n2 + " = " + r);
solved = true;
}
catch(InputMismatchException imme)
{
scan.nextLine();
System.out.println("The user enters textual data
instead of integers. Try again! \n");
}
catch(DivisionByZeroException dbze)
{
scan.nextLine();
System.out.println("The user attempts to
divide by zero. Try again! \n");
}
catch(Exception e)
{
scan.nextLine();
System.out.println(e.getMessage());
}
}
}
}
Output:
Please enter a value for n1: 6
Please enter a value for n2: R
The user enters textual data instead of integers. Try again!
Please enter a value for n1: 28
Please enter a value for n2: 0
The user attempts to divide by zero. Try again!
Please enter a value for n1: 81
Please enter a value for n2: 3
Result: 81/3 = 27.0