This chapter is from the book
This chapter is from the book
This chapter is from the book
Reference Types
To this point, you have seen a number of different data types. C# offers two primary ways of storing information: by value (byval) and by reference (byref). The basic data types that you have learned about store information by value.
When a variable stores information by value, the variable contains the actual information. For example, when you store 123 in an integer variable called x, the value of x is 123. The variable x actually contains the value 123.
Storing information by reference is a little more complicated. If a variable stores by reference, rather than storing the information in itself, it stores the location of the information. In other words, it stores a reference to the information. For example, if x is a "by reference" variable, it contains information on where the value 123 is located. It does not store the value 123. Figure 3.1 illustrates the difference.
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Figure 3.1 By reference versus by value.
The data types used by C# that store by reference are
- Classes
- Strings
- Interfaces
- Arrays
- Delegates
Each of these data types is covered in detail throughout the rest of this book.