Information Technology Reference
In-Depth Information
What Are Exceptions?
An
exception
is a runtime error in a program that violates a system or application constraint, or
a condition that is not expected to occur during normal operation. Examples are when a pro-
gram tries to divide a number by zero or tries to write to a read-only file. When these occur, the
system catches the error and
raises
an exception.
If the program has not provided code to handle the exception, the system will halt the
program.
For example, the following code raises an exception when it attempts to divide by zero:
static void Main()
{
int x = 10, y = 0;
x /= y; // Attempt to divide by zero--raises an exception
}
When this code is run, the system displays the following error message:
Unhandled Exception: System.DivideByZeroException: Attempted to divide by zero. at
Exceptions_1.Program.Main() in C:\Progs\Exceptions\Program.cs:line 12
