Visual C++ Typedefs in Class Designer

  • Article

Typedef statements create one or more layers of indirection between a name and its underlying type. The Class Designer supports C++ typedef types, which are declared with the keyword typedef, for example:

typedef class coord
{
   void P(x,y);
   unsigned x;
   unsigned y;
} COORD;

You can then use this type to declare an instance:

COORD OriginPoint;

Although you can declare a typedef without a name, Class Designer will not use the tag name that you specify; it will use the name that Class View generates. For example, the following declaration is valid, but it appears in Class View and Class Designer as an object named __unnamed:

typedef class coord
{
   void P(x,y);
   unsigned x;
   unsigned y;
};

For more information about using the typedef type, see typedef Specifier.

A C++ typedef shape has the shape of the type specified in the typedef. For example, if the source declares typedef class, the shape has rounded corners and the label Class. For typedef struct, the shape has square corners and the label Struct.

Classes and structures can have nested typedefs declared within them; therefore, class and structure shapes can show nested typedef declarations as nested shapes.

Typedef shapes support the Show as Association and Show as Collection Association commands on the context menu.

The following are some examples of typdef types that the Class Designer supports:

Code element

Class Designer view

typedef type name

name : type

typedef

Draws an association line connecting to type name, if possible.

typedef void (*func)(int)

func: void (*)(int)

typedef

Typedef for function pointers. No association line is drawn.

Class Designer does not display a typedef if its source type is a function pointer.

 
typedef int MyInt;
class A {
   MyInt I;
};

MyInt: int

typedef

A

Class

Draws an association line pointing from the source type shape to the target type shape.

Class B {};

typedef B MyB;

B

Class

MyB : B

typedef

Right-clicking a typedef shape and clicking Show As Association displays the typedef or class and an Alias of line joining the two shapes (similar to an association line).

typedef B MyB;

typedef MyB A;

MyBar : Bar

typedef

Same as above.

 
Class B {};
typedef B MyB;
class A {
   MyB B;
};

B

Class

MyB : B

typedef

A

Class

MyB is a nested typedef shape.

#include <vector>

...

using namespace std;

...

typedef vector<int> MyIntVect;

vector<T>Class

MyIntVect : vector<int>

typedef

class B {};

typedef B MyB;

class A : MyB {};

MyB : B

typedef

-> B

B

A

Class

-> MyB

Class Designer does not support displaying this kind of relationship by using a context menu command.

#include <vector>

Typedef MyIntVect std::vector<int>;

Class MyVect : MyIntVect {};

std::vector<T>

Class

MyIntVect : std::vector<int>

typedef

MyVect

Class

-> MyIntVect

See Also

Concepts

Working with Visual C++ Code in Class Designer

Reference

typedef Specifier