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Standard Template Library Programmer's Guide
(document number: 007-3426-004 / published: 1999-05-21) table of contents | additional info | download
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Generator


Category: functors	Component type: concept

Description

A Generator is a kind of function object: an object that is called as if it were an ordinary C++ function. A Generator is called with no arguments.

Refinement of

Assignable

Associated types

Result type

The type returned when the Generator is called

Notation

`F`	A type that is a model of Generator
`Result`	The result type of `F`
`f`	Object of type `F`

Definitions

The range of a Generator is the set of all possible value that it may return.

Valid expressions

Name	Expression	Type requirements	Return type
Function call	`f()`		`Result`

Expression semantics

Name	Expression	Precondition	Semantics	Postcondition
Function call	`f()`		Returns some value of type `Result` [1]	The return value is in `f`'s range.

Complexity guarantees

Invariants

Models

Result (*)()

Notes

[1] Two different invocations of f may return different results: a Generator may refer to local state, perform I/O, and so on. The expression f() is permitted to change f's state; f might, for example, represent a pseudo-random number generator.