C++ Primer Plus, Fourth Edition

Exceptions

Programs sometimes encounter runtime problems that prevent the program from continuing normally. For example, a program may try to open an unavailable file, or it may request more memory than is available, or it may encounter values it cannot abide. Usually, programmers try to anticipate such calamities. C++ exceptions provide a powerful and flexible tool for dealing with these situations. Exceptions were added to C++ recently, and not all compilers have implemented them yet.

Before examining exceptions, let's look at some of the more rudimentary options available to the programmer. As a test case, take a function that calculates the harmonic mean of two numbers. The harmonic mean of two numbers is defined as the inverse of the average ...