A Simple Example of Exception Processing

Usually, processing algorithms use C++ flow control statements, mostly the if or switch statements, to separate normal processing of data from processing of erroneous or faulty data. For multistep algorithms, the segment of source code for main algorithm and for exceptional conditions are written in alternative branches of the same source code, and this often makes code harder to read—the main line is lost in the multitude of exceptional and rare cases.

When something goes wrong in a function, the function might not know what to do about the error. Aborting the program might be a good solution in many situations, for example, trying to push an item onto a system stack that turns out to be full. On the other hand, aborting the program might not release resources held by the program, such as opened files or database locks.