Post on 18-Jan-2018
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COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
1
Conditional Statements
Concepts Covered:
Conditional StatementsSerially Arranged ConditionalsNested ConditionalsBoolean Expressions
Part 1Module 2
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
2
Conditional Statements
Concept: Conditional Statements
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
3
“control flow” and sequential execution
Open the trash lid
Drop empty can in trash
Close trash lid
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
4
“control flow” and conditional execution
Open the trash lid
Drop empty can in trash
Close trash lid
Is the trashcan’slid already up?
YESTRUE
NOFALSE
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
5
IF-THEN vs. IF-THEN-ELSE statements
Open the trash lid
Drop empty can in trash
Close trash lid
Is the trashcan’slid already up?
YESTRUE
NOFALSE
Yell: “Who left the
trash open!!!???”
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
6
Flowcharts vs. Pseudo Code
Open the trash lid
Drop empty can in trash
Close trash lid
Is the trashcan’slid already up?
YESTRUE
NOFALSE
IF <condition>THEN
<statements>ELSE
<statements>ENDIF
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
7
Conditional Statements
Application: Serially Arranged Conditionals
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Serial Arrangements
code #1a
code #2a
code #1b
Condition #1
Condition #2
code #2b
code #3
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Conditional Statements
Application: Nested Conditionals
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
10
Nested Arrangements
Code #1a
Code #2a
Code #1b
Condition #1
Condition #2
Code #2b
Code #3
Condition #3
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
11
Conditional Statements
Concept: Boolean Expressions
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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What’s in a conditional expression
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Drop empty can in trash
Close trash lid
Is the trashcan’slid already up?
YESTRUE
NOFALSE
What is a boolean expression?
evaluates into TRUE or FALSE only
e.g. Comparing variables / valuesa < b a <= 3 + b a + b >= 999
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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What’s in a conditional expression
Open the trash lid
Drop empty can in trash
Close trash lid
Is the trashcan’slid already up?
YESTRUE
NOFALSE
We can have several terms in a conditional expression
( a < b ) AND ( a > 0) ( a < b ) OR ( a > 0 )NOT ( a < b )
Do not assume left to right evaluationDo not assume lazy evaluationUntil you KNOW your programming language specifics
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Concept of Truth Table
( a < b ) AND ( a > 0) ( a < b ) OR ( a > 0 ) NOT ( a < b )
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Advices
Open the trash lid
Drop empty can in trash
Close trash lid
Is the trashcan’slid already up?
YESTRUE
NOFALSE
( a < b ) AND ( a > 0)
( a < b ) OR ( a > 0 )
NOT ( a < b )
Do not assume left to right evaluationDo not assume lazy evaluation
Until you KNOW your programming language specifics
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Multi-terms Boolean expressions to simplify
Display: “OK”
Display:“done”
(a<b) AND (a>0)
YESTRUE
NOFALSE
IF ( a < b ) AND ( a > 0) THEN
display “OK” ELSE
display “KO”ENDIF
display “done”
Display: “KO”
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Multi-terms Boolean expressions to simplify
Display: “OK”
Display:“done”
(a<b)YESTRUE
NOFALSE
IF ( a < b ) THEN
IF ( a > 0)THEN
display “OK” ELSE
display “KO”ENDIF
ELSE display “KO”
ENDIF
display “done”
Display: “KO”
(a>0)
Display: “KO”
YESTRUE
NOFALSE
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Multi-terms Boolean expressions to simplify
Display: “OK”
Display:“done”
(a<b) OR (a>0)
YESTRUE
NOFALSE
IF ( a < b ) OR ( a > 0) THEN
display “OK” ELSE
display “KO”ENDIF
display “done”
Display: “KO”
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
19
Multi-terms Boolean expressions to simplify
Display: “OK”
Display:“done”
(a<b)YESTRUE
NOFALSE
IF ( a < b ) THEN
display “OK” ELSE
IF ( a > 0)THEN
display “OK” ELSE
display “KO”ENDIF
ENDIF
display “done”
Display: “KO”
(a>0)
Display: “OK”
YESTRUE
NOFALSE
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
20
Multi-terms Boolean expressions to simplify
Display: “OK”
Display:“done”
(a<b) XOR (a>0)
YESTRUE
NOFALSE
IF ( a < b ) XOR ( a > 0) THEN
display “OK” ELSE
display “KO”ENDIF
display “done”
Display: “KO”
COP 2510 Programming Concepts Alessio GasparBSAS Industrial Operations
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Multi-terms Boolean expressions to simplify
KO
Display:“done”
(a<b)YESTRUE
NOFALSEIF ( a < b )
THEN IF ( a>0 )THEN display “KO” ELSE display “OK”ENDIF
ELSE IF ( a > 0)THEN display “OK” ELSE display “KO”ENDIF
ENDIF
display “done”
KO
(a>0)
OK
YESTRUE
NOFALSE
(a>0)
YESTRUE
NOFALSE
OK