Mata kuliah : M0874 – Programming II
Tahun
: 2010
Control Structures
Session 03
Outline Materi
•Pseudocode
•Control Structure
•If Selection Structure
•If/else Selection Structure
•While Repetition Structure
•Assignment Operators
•Increment and Decrement Operators
•For Repetition Structure
•Switch Multiple-Selection Structure
•Do/While Repetition Structure
•Statements break and continue
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Pseudocode
•An artificial an informal language that helps
programmers develop algorithms.
•Similar to everyday english; it is convenient and
user-friendly, and it is not an actual computer
programming language.
•Not executed on computers.
•Helps the programmer “think out” a program before
attempting to write it in a programming language.
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Control Structure
•Three types of selection structures:
•If selection structure
•If/else selection structure
•Switch selection structure
•Four repetition structures:
•While
•Do/while
•For
•Foreach
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If Selection Structure
If student’s grade is greater than or equal to 60
Print “passed”
Pseudocode if statement:
if ( studentGrade >= 60 )
Console.WriteLine ( “Passed” );
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Flow chart If Selection Structure
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If/else Selection Structure
If student’s grade is greater than or equal to 60
Print “Passed”
else
Print “Failed”
Pseudocode if/else structure:
if ( studentGrade >= 60 )
Console.WriteLine( “Passed” );
else
Console.WriteLine( “Failed” );
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Flow Chart If/else Selection Structure
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Nested if/else
if student’s grade is greater than or equal to 90
Print “A”
else
if student’s grade is greater than or equal to 80
Print “B”
else
if student’s grade is greater than or equal to 60
Print “C”
else
Print “D”
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Nested if/else
Pseudocode may be written as:
if ( studentGrade >= 90 )
Console.WriteLine ( “A” );
else
if ( studentGrade >= 80 )
Console.WriteLine ( “B” );
else
if ( studentGrade >= 60 )
Console.WriteLine( “C” );
else
Console.WriteLine( “D” );
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Nested if/else
Most C# programmers prefer to write the preceding
if structure as:
if ( studentGrade >= 90 )
Console.WriteLine ( “A” );
else if ( studentGrade >= 80 )
Console.WriteLine ( “B” );
else if ( studentGrade >= 60 )
Console.WriteLine( “C” );
else
Console.WriteLine( “D” );
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While Repetition Structure
•Specify that an action is to be repeated while a
condition remains true.
•The pseudocode statement
While there are more items on my shopping list
Purchase next item and cross it off my list
Example:
int product = 2;
while ( product <= 1000 )
product = 2 * product
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While Repetition Structure
true
product <= 1000
product = 2 * product
false
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Assignment Operators
Assume:
int c = 3, d = 5, e = 4, f = 6, g = 12
Assignment operator
Sample expression
Explanation
Assigns
+=
c += 7
c=c+7
10 to c
-=
d -= 4
d=d-4
1 to d
*=
e *= 5
e=e*5
20 to e
/=
f /= 3
f=f/5
2 to f
%=
g %= 9
g=g%9
3 to g
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Increment and Decrement Operators
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Increment and Decrement Operators
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Increment and Decrement Operators
•Output:
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For Repetition Structure
for ( expression1; expression2; expression3 )
statement
for keyword
counter variable name
final value of control variable
for ( int counter = 1; counter <= 5; counter++ )
Initial value of control variable loop-continuation condition increment of
control var
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For Repetition Structure
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For Repetition Structure
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Switch Multiple-Selection Structure
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Do/While Repetition Structure
•Do/while repetition structure is similar to the while
structure.
•In the while structure, the test of the loopcontinuation condition occurs at the beginning of the
loop, before the body of the loop executes.
•The do/while structure tests the loop-continuation
condition after the loop body executes; therefore,
the loop body always executes at least once.
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Do/While Repetition Structure
do
statement
while ( condition );
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OR
do
{
statement
} while ( condition );
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Do/While Repetition Structure
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Statements break and continue
•The break and continue statements alter the flow of
control.
•The break statement, when executed in a while, for,
do/while or switch structure, cause immediate exit
from that structure.
•The continue statement, when executed in a while,
for or do/while structure, skips the remaining
statements in the body of that structure and
proceeds with the next iteration of the loop.
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Statements break and continue
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Statements break and continue
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References
•http://books.google.co.id/books?id=8R451rZJ5o0C
&printsec=frontcover&dq=c%23&cd=2#v=onepage&
q=&f=false
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