C# 0 The Complete Reference

Exception

 constructor via 

base

. Of course, technically, you need to provide only those 

constructors actually used by your program.

Here is an example that makes use of a custom exception type. At the end of Chapter 10 

an array class called 

RangeArray

 was developed. As you may recall, 

RangeArray

 supports 

single-dimensional

int

 arrays in which the starting and ending index is specified by the 

user. For example, an array that ranges from –5 to 27 is perfectly legal for a 

RangeArray

.

In Chapter 10, if an index was out of range, a special error variable defined by 

RangeArray

was set. This meant that the error variable had to be checked after each operation by the 

code that used 

RangeArray

. Of course, such an approach is error-prone and clumsy. A far 

better design is to have