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Chapter II

Control Statements

Java ProgrammingCOSC 450

Dr. Mohamad EL ABED

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Chapter II - Objectives

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To be able to use the if and ifelse selection

To be able to use the while repetition structure to execute

statements in a program repeatedly

To be able to use the increment, decrement and assignment

operators

To understand multiple selection using the switch selection

structure

To be able to use the logical operators

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators Increment and Decrement Operators

Logical Operators

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The if Selection Statement

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The ifselection statement either performsan action if a condition

is true or skipsthe action if the condition is false

Code if(condition)

Actions

If selection flowchart

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The if Selection Statement

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If selection flowchart Java language

Example Students grade

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Chapter II - Outline

6

The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators Increment and Decrement Operators

Logical Operators

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The ifelse Selection Statement

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The ifelseselection statement performsan action if a condition

is true and performsa different action if the condition is false

Code if(condition)

Actions I

else

Actions II

Ifelse selection flowchart

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The ifelse Selection Statement

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Ifelse selection flowchart Java language

Example Students grade

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators Increment and Decrement Operators

Logical Operators

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switch Multiple-Selection Statement

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o So far, we have only seen binaryselection

o Sometimes it is necessary to branch in more thantwo directions

o

We do this via multiple selectiono Javaprovides the switchmultiple-selection statement to handle

such decision making

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switch Multiple-Selection Statement

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o The switchstatement consists of a series of case labels, an

optionaldefault caseand statementsto execute for each case

switch ( expression){case value1:

statement-list1

case value2:

statement-list2

case

default:

statement-list

}

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switch Multiple-Selection Statement

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Problem Statement

Using the switch statement, write a program that outputs the

integer given by a user in the following way:

o 1 -> "One"

o 2 -> "Two"

o 3 -> "Three"

o Other numbers -> output a message "Bigger than three"

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switch vs if Statement

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switch vs if Statement

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The switchstatement is more efficient than an ifstatement in

terms of performance (i.e., running time)

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators Increment and Decrement Operators

Logical Operators

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switch vs ifelse Statement

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switch vs ifelse Statement

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o A nested ifelsestructure is just as efficient as a switch

statement

o

However, a switchstatement may be easierto read

o Also, it is easier to add new cases to a switchstatement than to

a nested ifelsestructure.

o A nested ifelsestructure is then more efficient than an if

statement in terms of performance (i.e., running time)

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators

Increment and Decrement Operators

Logical Operators

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The for Repetition Statement

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The forrepetition statement handlesall the details of counter-

controlled repetition

Code for ( ; ; )

Actions

Initialization of the control variable

Loop-continuation condition

Increment of control variable

for repetition flowchart

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The for Repetition Statement

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Example Write a program that prints the numbers from 1 to 10

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The for Repetition Statement

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Example Write a program that prints the numbers from 1 to 10

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators

Increment and Decrement Operators

Logical Operators

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The while Repetition Statement

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A repetition statementallows you to specify that an action is to

be repeated while some condition remains true

Code while(condition)

Actions

while repetition flowchart

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The while Repetition Statement

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Problem Statement

A program designed to find the first power of 2 larger than 1000

while repetition flowchart Java language

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators

Increment and Decrement Operators

Logical Operators

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Assignment Operators

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators

Increment and Decrement Operators

Logical Operators

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Increment and Decrement Operators

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Chapter II - Outline

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The if Selection Statement

The ifelse Selection Statement

switch Multiple-Selection Statement

Switch vs if Statement

Switch vs ifelse Statement

The for Repetition Statement

The while Repetition Statement

Assignment Operators

Increment and Decrement Operators

Logical Operators

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Logical Operators

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o So far, we have studied only simple conditions, such as

o Sometimes it is necessary to test multiple conditionsin the

process of making a decision

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Logical Operators

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o We do this via logical operators

o Truth table for the logical ANDoperator (&&)

Logical Operator Name

&& Logical AND

|| Logical OR

! Logical NOT

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Logical Operators

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o Truth table for the logical ORoperator (||)

o Truth table for the logical NOT(!)

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