## 3.2.2 Default Initialization

Default initialization occurs if initialization appears in a derived-type component definition. (This is a Fortran 95 feature.)

The specified initialization of the component will apply even if the definition is PRIVATE.

Default initialization applies to dummy arguments with INTENT(OUT). It does not imply the derived-type component has the SAVE attribute.

Explicit initialization in a type declaration statement overrides default initialization.

To specify default initialization of an array component, use a constant expression that includes one of the following:

- An array constructor
- A single scalar that becomes the value of each array element

Pointers can have an association status of associated, disassociated, or undefined. If no default initialization status is specified, the status of the pointer is undefined. To specify disassociated status for a pointer component, use =>NULL( ).

Examples

You do not have to specify initialization for each component of a derived type. For example:

    TYPE REPORT
      CHARACTER (LEN=20) REPORT_NAME
      INTEGER DAY
      CHARACTER (LEN=3) MONTH
      INTEGER :: YEAR = 1995        ! Only component with default
    END TYPE REPORT                 !      initialization

Consider the following:

    TYPE (REPORT), PARAMETER :: NOV_REPORT = REPORT ("Sales", 15, "NOV", 1996)

In this case, the explicit initialization in the type declaration statement overrides the YEAR component of NOV_REPORT.

The default initial value of a component can also be overridden by default initialization specified in the type definition. For example:

    TYPE MGR_REPORT
      TYPE (REPORT) :: STATUS = NOV_REPORT
      INTEGER NUM
    END TYPE MGR_REPORT

    TYPE (MGR_REPORT) STARTUP

In this case, the STATUS component of STARTUP gets its initial value from NOV_REPORT, overriding the initialization for the YEAR component.

Previous Page Next Page Table of Contents