Java Reference
In-Depth Information
ception handling so that if the user makes a mistake, the program catches and handles (i.e.,
deals with) the exception—in this case, allowing the user to re-enter the input.
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// Fig. 11.3: DivideByZeroWithExceptionHandling.java
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// Handling ArithmeticExceptions and InputMismatchExceptions.
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import
java.util.InputMismatchException;
import
java.util.Scanner;
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public
class
DivideByZeroWithExceptionHandling
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{
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// demonstrates throwing an exception when a divide-by-zero occurs
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public
static
int
quotient(
int
numerator,
int
denominator)
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throws
ArithmeticException
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{
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return
numerator / denominator;
// possible division by zero
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}
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public
static
void
main(String[] args)
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{
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Scanner scanner =
new
Scanner(System.in);
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boolean
continueLoop =
true
;
// determines if more input is needed
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do
{
try
// read two numbers and calculate quotient
{
System.out.print(
"Please enter an integer numerator: "
);
int
numerator = scanner.nextInt();
System.out.print(
"Please enter an integer denominator: "
);
int
denominator = scanner.nextInt();
int
result = quotient(numerator, denominator);
System.out.printf(
"%nResult: %d / %d = %d%n"
, numerator,
denominator, result);
continueLoop =
false
;
// input successful; end looping
}
catch
(InputMismatchException inputMismatchException)
{
System.err.printf(
"%nException: %s%n"
,
inputMismatchException);
scanner.nextLine();
// discard input so user can try again
System.out.printf(
"You must enter integers. Please try again.%n%n"
);
}
catch
(ArithmeticException arithmeticException)
{
System.err.printf(
"%nException: %s%n"
, arithmeticException);
System.out.printf(
"Zero is an invalid denominator. Please try again.%n%n"
);
}
}
while
(continueLoop);
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}
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}
// end class DivideByZeroWithExceptionHandling
Fig. 11.3
|
Handling
ArithmeticException
s and
InputMismatchException
s. (Part 1 of 2.)
