blob: 2a22229d32dac6d845053227782f72d43c0d1bb4 (
plain)
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
|
// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
/*!
\example statemachine/factorial
\title Factorial States Example
\ingroup examples-qtstatemachine
\brief The Factorial States example shows how to use \l{Qt State Machine Overview}
to calculate the factorial of an integer.
The statechart for calculating the factorial looks as follows:
\image factorial-example.png
In other words, the state machine calculates the factorial of 6 and prints
the result.
\snippet 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 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 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 statemachine/factorial/main.cpp 3
The application's main() function first creates the application object, a
Factorial object and a state machine.
\snippet 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 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 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.
*/
|
