8.3. Handling Exceptions

The first line of defense in an application is to check for potential error conditions before performing an operation. For example, a program can explicitly check whether the divisor is 0 before performing a calculation, or if a file exists before attempting to open it:

if (divisor != 0)
    // It's safe to divide some number by divisor.

if (System.IO.File.Exists("myfile.txt"))
    // You can now open the myfile.txt file.
    // However, you should still use exception handling because a variety of
    // problems can intervene (insufficient rights, hardware failure, etc.).

Even if you perform this basic level of "quality assurance," your application is still vulnerable. For example, you have no way to protect against all the ...

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