Operator For (Iteration)

FreeBASIC

Declares or defines operators used by a For...Next loop with user defined type variables

Syntax

{ Type | Class | Union } typename Declare Operator For () Declare Operator For ( [ ByRef | ByVal ] stp As typename ) ... End { Type | Class | Union }

Usage

For iterator [ As typename ] = start_value To end_value [ Step step_value ] [ ...statements... ] Next

Parameters

typename

name of the Type, Class, or Union

stp, step_value

a typename object used as an incremental value

iterator

a typename object used as an iterator

end_value

a typename object used as a loop-terminating value

start_value

a typename object used to copy construct or assign to the iterator initially

Description

Operator For, Operator Next and Operator Step can be overloaded in user-defined type definitions to allow objects of that type to be used as iterators and step values in For...Next loops.

Operator For is called immediately after copy constructing or assigning to the iterator object, and allows the object to perform any additional initialization needed in preparation for the loop.

The first version of Operator For is used if no step value is given in the For...Next statement. If a step value is given, the second version is used and is passed the step value.

Example

See the Operator Step examples.

Dialect Differences

Only available in the -lang fb dialect.