10. Organizing Exceptions

Errors in a program can be classified into the following categories: compile-time errors and runtime errors. Compile-time errors are comparatively easy to fix because you know about them much earlier (i.e., at compile time). These may occur mainly due to syntax errors or typing mistakes. The compiler can point to them so that you can take corrective measures immediately. By contrast, runtime errors are dangerous because you encounter them when a program is executing. Programmatically, we call them exceptions. Since the program was compiled earlier, you expected it to run successfully. Why do exceptions occur? These may occur through some careless mistakes; maybe you have implemented the wrong logic, you have ignored some loopholes in the code paths of the program, etc. This type of error is tough to handle and is costly. Even after our best efforts, often these situations are unavoidable. It is also true that many of the failures are beyond the control of a programmer. So, handling these runtime errors is essential when you write an application. C#’s exception handling mechanism is important because it helps you deal with these typical runtime errors in advance.