|
|
|
|
|
|
|
Variable ReferenceToVariable is a pointer to myVariable. |
|
|
|
|
|
|
|
|
The only place where references are regularly used is with certain types of structures in the OLE subsystem. When you see a reference data type, just treat it as if it were a pointer, and you'll do fine. |
|
|
|
|
|
|
|
|
These terms are used to define user-defined types in the C language. You'll find out a lot more about how to handle classes and structures as you proceed through this book. From a Visual Basic programmer's perspective, there is no difference between a class and a structure. They are defined as follows: |
|
|
|
|
|
|
|
|
class myClass {
Define variables within the structure here
}; |
|
|
|
|
|
|
|
|
So far you've seen that the C language actually specifies the following keywords for data types: char, short, int, long, float, and double, as well as the following modifiers: |
|
|
|
|
|
|
|
|
unsigned: Indicates the data is unsigned. There is also a signed keyword, but it is rarely used because the default is signed. |
|
|
|
|
|
|
|
|
[ ]: Indicate an array of a fundamental data type. |
|
|
|
|
|
|
|
|
*: Indicates a pointer to a data type. |
|
|
|
|
|
|
|
|
&: Indicates the address of a variable or a reference to a variable. |
|
|
|
|
|
|
|
|
Despite the shortness of this list, any API or DLL documentation you see will have dozens of additional data types. Where do they come from? |
|
|
|
|
|
|
|
|
The answer lies in the fact that the C language allows you to derive new data types from existing data types. This is done using a statement called "typedef." For example, consider the statement: |
|
|
|
|
|
|
|
|
typedef unsigned char BYTE; |
|
|
|
|
|