COMP102

1
COMP102 Programming Fundamentals I

• LA2B (Mon 5-7pm)
• LA2E (Fri 3-5pm)
• LA2F (Fri 5-7pm)
• TA Jackie Lo

2
Lecture Review

• if statement
• Provides the means of choosing
• Between two or more execution paths in a program
• E.g. In ATM,
• if user key in correct password?
• correct allow user to cash-out money
• not correct force user to quit

3
Lecture Review

• Syntax
• if (condition)
• action
• if (condition)
• action_1
• else
• action_2

• if (condition_1)
• action_1
• else if (condition_2)
• action_2
• else if (condition_3)
• action_3
• else action_4

4
Lecture Review

• Example
• if (exam mark is larger than 49)
• exam passed
• if (exam mark is larger than 49)
• exam passed
• else
• retake exam

5
Lecture Review

• Example
• if (exam mark is larger than 89)
• A grade
• else if (exam mark is larger than 69)
• B grade
• else if (exam mark is larger than 59)
• C grade
• else if (exam mark is larger than 49)
• D grade
• else F grade

6
Lecture Review

• Relational Operators
• is equal to
• lt is smaller than
• lt is smaller than or equal to
• gt is larger than
• gt is larger than or equal to
• ! not equal to
• E.g.
• (10 gt 8) True
• (8 6) False
• (8 lt 8) True

7
Lecture Review

• Example
• if (exam_mark gt 89)
• coutltltA grade
• else if (exam_mark gt 70)
• coutltltB grade
• else if (59 lt exam_mark)
• coutltltC grade
• else if (50 lt exam_mark)
• coutltltD grade
• else coutltltF grade

8
Lecture Review

• Boolean Operators
• and
• or
• ! Not
• E.g.
• if (is_102TA is_girl)
• cout ltltHello Jackie!ltltendl
• if (is_102TA is_helpYou)
• cout ltltYou are so nice, Thank you!ltltendl

9
Leeture Review

• Nested if Statement
• if statement is inside another if

if (condition_1) if (condition_2) if
(condition_3) action_1
action_2a else action_2b
action_3
10
Summary

• By the end of this lab, you should be able to
• Implement if statement
• Set condition with
• Relational operators
• Boolean operators
• Use shortcut assignment

11
Lab3

• Use if-statement

coutltlt cingtgtgreater_than_18 if
(greater_than_18 y greater_than_18
Y) coutltlt cingtgtname // input height
and weight BMI // coutltltDear
ltltnameltlt,ltltendl // output the 1st paragraph
of advice letter //use if-statement to give
different advice according to BMI
/ / // output the rest of the advice
letter else coutltltltltendl