11st Semester 2005

Module4-1 Module4-1 Iteration statement - whileIteration statement - while

อภิ�รั�กษ์� จั�นทรั�สรั�างAphirak Jansang

aphirak.j@ku.ac.thhttp://www.cpe.ku.ac.th/~aphirak

Computer Engineering DepartmentKasetsart University, Bangkok THAILAND

22/39/391st Semester 2005

Outline Review condition statement Loop statements

while statement do…while statement for statement

break statement

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Simple C# Structure Namespace

Class Main()

NamespaceNamespace

ClassClass

Main()Main()

Variable & Constant LocationVariable & Constant Location

statementsstatementsWriteLine, ReadLine, if, switch, LoopWriteLine, ReadLine, if, switch, Loop

Review condition statementReview condition statement

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Condition Statements

if (conditioncondition) statement; if (conditioncondition)

statement1;else statement2;

switch (<(<expressionexpression>)>){ case <constant-expression>: <statements>; break;

default: <statements>; break;}

Review condition statementReview condition statement

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Outline Review condition statement Loop statements

while statement do…while statement for statement

break statement

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Loop or Iteration in C#

forfor

whilewhile

do…whiledo…while

foreachforeachIterationIteration

Loop statementsLoop statements

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C# Program with ConditionStart

statement1

statement2

statement3 statement4

End

Conditiontruetrue falsefalse

Loop statementsLoop statements

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Simple C# ProgramStart

statement1

statement1

statement1

statement1

End

statement1

Loop statementsLoop statements

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Simple C# Program with LoopStart

x=5;

statement1

x=x-1;

End

x>0

truetrue

falsefalse

Loop statementsLoop statements

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Outline Review condition statement Loop statements

while statement do…while statement for statement

break statement

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while statement

conditioncondition

statementstatement

truetrue

falsefalsewhile (condition) statement;

while statementwhile statement

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while statement – more statements

while (condition) { statement1; statement2;}

conditioncondition

statement1statement1

truetrue

falsefalse

statement2statement2

while statementwhile statement

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Example1:while statement

22nn = ??? = ??? n = 5n = 5

result=2*2*2*2*2result=2*2*2*2*2 = 32= 32

result=1;

result = result*2;

n=n-1;

n>0

truetrue

falsefalse

n=5;

Display resultDisplay result

See demo program!!!!See demo program!!!!prog2-loop.csprog2-loop.cs

while statementwhile statement

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Example2:while statement

n = 5n = 5

result = 1+2+3+4+5result = 1+2+3+4+5 result=0;

result = result+n;

n=n-1;

n>0

truetrue

falsefalse

n=5;

Display resultDisplay result

See demo program!!!!See demo program!!!!prog3-loop.csprog3-loop.cs

n

i

i1

while statementwhile statement

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Iteration Template Counter Controlled Sentinel Controlled

while statementwhile statement

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Counter Controlled Control Variable – counter variable

Three component Initial counter variable condition (counter variable is still valid?) Incrementing/Decrementing counter

variable

while statement: counter controlledwhile statement: counter controlled

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Example3:Count Controlled

Display 1 – 7 on screeninitial counter

statement;

dec||inc counter

condition

truetrue

falsefalse

See demo program!!!!See demo program!!!!prog4-loop.csprog4-loop.cs

while statement: counter controlledwhile statement: counter controlled

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Break!!!! (5 minutes)(Elevator) Neo: There is no spoon... Morpheus: Neo, sooner or later you're

going to realize, just as I did, there's a there's a difference between knowing the difference between knowing the path and walking the pathpath and walking the path......

Trinity: Run, Neo . Run ! What is he doing? Morpheus: He's beginning to believe* From The Matrix

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Iteration Template Counter Controlled Sentinel Controlled

while statementwhile statement

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Sentinel Controlled Input driven program

#repetition cannot tell depend on condition and input

Sentinel Value Causes loop to break

while statement: sentinel controlledwhile statement: sentinel controlled

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Example4:Sentinel Controlled

Find summation from user input Exit program when user input

negative number

See demo program!!!!See demo program!!!!prog5-loop.csprog5-loop.cs

while statement: sentinel controlledwhile statement: sentinel controlled

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Break 3 Minutes

““With With great powergreat power comes with comes with great responsibilitygreat responsibility””

*From Spiderman*From Spiderman

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Example 5: Display n stars

See demo program!!!!See demo program!!!!prog6-loop.csprog6-loop.cs

while statement: examplewhile statement: example

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Example 6: Display stars

See demo!!!!See demo!!!!prog7-loop.csprog7-loop.cs

while statement: examplewhile statement: example

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Example 7: Display stars

See demo!!!!See demo!!!!prog8-loop.csprog8-loop.cs

while statement: examplewhile statement: example

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Example 8: Display stars

See demo!!!!See demo!!!!prog9-loop.csprog9-loop.cs

while statement: examplewhile statement: example

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Summary Loop statements

while statement do…while statement for statement

break statement