软件工程第12讲
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4.2.1.2 Some Concepts
1.Depth: represents the number of levels of control;
2.Width:represents the number of overall span of control;
3.Fan-in:indicates how many modules directly control a given module;
4.Fan-out:represents the number of modules that are directly controlled by another module;
5.Superordinate and subordinate: (p166).
A module that controls another module is said to be superordinate to it; conversely, a module controlled by another is said to be subordinate to the controller .
e.g.
4.2.2 Software procedure description General detailed design tools:
Graphic tools:procedure details represent the part of graphics;
Design language(language tool):using pseudo code represents procedural details;
T a b u l a r t o o l:u s i n g t a b l e r e p r e s e n t s procedural details.
4.2.2.1 Graphic tools
1. Structured Flowcharts pp.216
Sequence If-then-else
or
Do-while
Structured Flowcharts (cont.)
Repeat-until
Selection
e.g. pp.218
2. N-S charts (Box diagram) pp.218
e.g. pp.218
3. Problem Analysis Diagram (PAD)
PAD constructs
e.g.
4.2.2.2 Language tool
e.g. pp.222
PROCEDURE security.monitor；INTERFACE RETURNS system.status；TYPE signal IS STRUCTURE DEFINED name IS STRING LENGTH VAR;
address IS HEX device location；
bound.value IS upper bound SCALAR：
message IS STRING LENGTH VAR：END signal TYPE;
TYPE system.status IS BIT(4);
TYPE alarm.type DEFINED
smoke.alarm IS INSTANCE OF signal；
fire.alarm IS INSTANCE OF signal；
water.alarm IS INSTANCE OF signal；
temp.alarm IS INSTANCE OF signal：
burglar.alarm IS INSTANCE OF signal；
TYPE phone.number IS area code+7-digit number；
…
initialize all system ports and reset all hardware；CASE OF control.panel.switches(cps):
WHEN cps=“test”SELECT
CALL alarm PROCEDURE WITH
“on” for test.time in seconds；
WHEN cps=“alarm-off” SELECT
CALL alarm PROCEDURE WITH
“off”；
WHEN cps=“new.bound.temp”SELECT
CALL keypad.input PROCEDURE;
WHEN cps=“burglar.alarm.off” SELECT
deactivate signal[burglar.alarm]；
…
DEFAULT none；
ENDCASE
REPEAT UNTIL activate.switch is turned off
reset all signal.values and switches；
DO FOR alarm.type=smoke,fire,water,temp,burglar；
READ address[alarm.type] signal.value；
IF signal.value>bound[alarm.type]
THEN phone.message=message[alarm.type]；
set alarm.bell to“on”for alarm.time in seconds；
PARBEGIN
CALL alarm PROCEDURE WITH “on”，alarm.time in seconds
CALL phone PROCEDURE WITH message[alarm.type],phone.number；
ENDPAR
ELSE skip
ENDIF
ENDFOR
ENDREP
END security.monitor