1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\example statemachine/factorial
\title Factorial States Example
The Factorial States example shows how to use \l{The State Machine
Framework} to calculate the factorial of an integer.
The statechart for calculating the factorial looks as follows:
\img factorial-example.png
\omit
\caption This is a caption
\endomit
In other words, the state machine calculates the factorial of 6 and prints
the result.
\snippet examples/statemachine/factorial/main.cpp 0
The Factorial class is used to hold the data of the computation, \c x and
\c fac. It also provides a signal that's emitted whenever the value of \c
x changes.
\snippet examples/statemachine/factorial/main.cpp 1
The FactorialLoopTransition class implements the guard (\c x > 1) and
calculations (\c fac = \c x * \c fac; \c x = \c x - 1) of the factorial
loop.
\snippet examples/statemachine/factorial/main.cpp 2
The FactorialDoneTransition class implements the guard (\c x <= 1) that
terminates the factorial computation. It also prints the final result to
standard output.
\snippet examples/statemachine/factorial/main.cpp 3
The application's main() function first creates the application object, a
Factorial object and a state machine.
\snippet examples/statemachine/factorial/main.cpp 4
The \c compute state is created, and the initial values of \c x and \c fac
are defined. A FactorialLoopTransition object is created and added to the
state.
\snippet examples/statemachine/factorial/main.cpp 5
A final state, \c done, is created, and a FactorialDoneTransition object
is created with \c done as its target state. The transition is then added
to the \c compute state.
\snippet examples/statemachine/factorial/main.cpp 6
The machine's initial state is set to be the \c compute state. We connect
the QStateMachine::finished() signal to the QCoreApplication::quit() slot,
so the application will quit when the state machine's work is
done. Finally, the state machine is started, and the application's event
loop is entered.
*/
|
