# Hierarchy Browser

Inheritance, a type of relationship between objects, allows one object to share behavior with one or more other objects (sharing with more than one is known as multiple inheritance). Inheritance provides the basic mechanism for the reuse of code. The Hierarchy Browser helps you to understand class hierarchy trees, which in turn helps you to reuse existing code.

## Using the Hierarchy Browser

Start the Hierarchy Browser in one of the following ways:

- choose Windows -> New -> Hierarchy.
- click the Hierarchy toolbar button (see Hierarchy Browser Button).
- choose the Hierarchy tab in the Editor.

The Hierarchy Browser can display the entire class hierarchy, including the superclasses and subclasses of a selected class.

#### Hierarchy Browser Window

### Tools Menu

The Tools -> Hierarchy menu contains the following items, which control how the class hierarchies are displayed.

Show Superclasses
Limits the hierarchy to the superclasses (and their subclasses) of the selected class.

Show Subclasses
Limits the hierarchy to the subclasses of the selected class.

Show All
This is the default for this menu.

Display file name
Displays the file names of the superclasses and subclasses.

### Class/Hierarchy Preferences

Many of the settings that control how the Hierarchy window functions are located in the Class/Hierarchy tab of the Preferences dialog. To find this window:

1. Select File -> Project -> Project Preferences... from the Symbol Browser, or select Edit -> View Preferences... from the Hierarchy Browser.
2. Choose the Class/Hierarchy tab.

#### Class/Hierarchy Tab of the Preferences Dialog

#### Class

Go To
Select Declaration if you want the Class Browser to display the prototype of the function; select Implementation if you want to see the actual code. Use Ctrl+Shift+D and Ctrl+Shift+I in Windows or Alt+D and Alt+I in UNIX to toggle between them.

Orientation
Select Horizontal to have the Hierarchy appear below of the Class Browser; select Vertical to have the Hierarchy appear to the right the Class Browser.

Display members
Select First to cause instance variables to appear before methods in the Class Browser; select Second to cause methods to appear first, with the instance variables after them.

#### Hierarchy Layout

Display order:
Left to right displays the hierarchy from left to right in the main window; Top to Bottom displays the hierarchy from top to bottom.

Display layout style:
Select Tree to display the hierarchy in tree layout; select ISI to display the hierarchy in ISI layout.

Vertical space:
Enter the number of vertical pixels between symbols in the Hierarchy window.

Horizontal space:
Enter the number horizontal pixels between symbols in the Hierarchy window.

### Hierarchy Browser Shortcut Keys

These shortcut keys are available for use with the Hierarchy Browser.

Key Combinations | Function
--- | ---
Windows | UNIX |
Alt+B | Meta+B | Starts the Class Browser for the marked class.