Transcript Chapter 7 power point

Internet & WWW
How to program
Chap.(7)
JavaScript: Control Statements I
Dr. Qusai Abuein
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(7.1) Introduction
• This chapter introduces a general theoretical
understanding of the structured programming.
• The if statement as a control one in the program in
introduced.
• Some reserved words (Keywords) used in the
JavaScript. Fig. 7.2.
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(7.2, 7.3, 7.4) Self Study
• Algorithms
• Pseudocode
• Control Structure
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(7.5) The IF statement
• Same as in the programming language you know
(c++).
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(7.6) If … else statement
• Same as in the programming language you know
(c++).
• The Nested if is also the same as you expect.
• The conditional operator (?:) is also supported.
– document.writeln(grade >= 60 ? ”pass” : “faile”)
• Nested if … else statement is also supported.
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(7.7, 7.8) While repetition Statement
• Example in Fig. 7.7 uses the while repetition
statement using a counter (fixed value such as 10,
or a number “n” read previously by the user) to
control the loop (also syntax and concept as you
expect).
• Un initialized variables used in calculations
result in logic errors and produce the value NaN.
See lines 19 and 20 in Fig.7.7 . The calculation
is used in line 33.
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(7.9) Repetition Example
• The example in Fig.7.9 uses a special value
called a sentinel value (also called a signal value,
a dummy value or a flag value such as “-1”) to
stop or control the while loop.
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(7.10) Repetition Example
•
The example in Fig.7.11 introduces counters in
the program:
–
–
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•
One to count number of students
Other to count passes results
And other to count filed results
Any logical errors in the program ?
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(7.11) Assignment Operators
•
JavaScript provides several compound assignment
operators.
–
–
–
–
–
•
C += 3;
C -= 3;
C *= 3;
C /= 3;
C %= 3;
See Fig. 7.11
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(7.12) Increment and decrement
•
•
•
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The increment operator ++ is provided by
JavaScript.
Also the decrement one --.
Fig.7.14 shows the difference between
pre-increment and post-increment.
See Fig. 7.15 for precedence of operators.
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End of Chap. (7)
Thank you .
Dr. Qusai Abuein
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