Control

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Control

• Conditionals...Loops
• Comments...Constants

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Conditionals

• The simple case
• if(ltboolean_valuegt)
• single_statement

• OR
• if(ltboolean_valuegt)
• statements

This can be dangerous!!!
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The Classic Killer Error

• if(ltsome_booleangt)
• statement
• statement

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Conditionals

• Adding the else part
• if(ltboolean conditiongt)
• statement
• statement
• else
• statement
• statement

Example if( leapYear ) febDays
29 else febDays 28
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Conditionals

• Adding the else part
• if(ltboolean conditiongt)
• statement
• statement
• else
• statement
• statement

Example if( leapYear ) febDays 29 else
febDays 28
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Loops -- Sentinel

• Pseudocode
• total, i isoftype Num
• total lt- 0
• i lt- 1
• loop
• exitif(i gt 10)
• total lt- total i
• i lt- i 1
• endloop

• Java
• int total, i
• total 0
• i 0
• while(i lt 10)
• total total i
• i i 1

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Loops -- Test Last

• Pseudocode
• total, i isoftype Num
• total lt- 0
• i lt- 1
• loop
• total lt- total i
• i lt- i 1
• exitif(i gt 10)
• endloop

• Java
• int total, i
• total 0
• i 1
• do
• total total i
• i i 1
• while(i lt 10)

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for Loops

• for(ltinitgt ltwhile_booleangt ltincgt)
• statement
• ltinitgt is done before entering loop
• ltwhile_booleangt is checked before entering and
  before each subsequent iteration and must be true
• ltincgt is performed at the end of each iteration.
• Note ltinitgt and ltincgt can be multiple statements
  but for now dont do it!

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Loops -- Convenience!

• Classic while loop
• int total 0
• int i 0
• while(i lt 10)
• total total 1
• i i 1

• for loop
• int total 0
• int i
• for(i 0 i lt 10 i)
• total total 1

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Loops Summarized

• while(ltbooleangt)
• statement(s)
• do
• statement(s)
• while(ltbooleangt)
• for(ltinitgt ltwhile_booleangt ltincgt)
• statement(s)

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Shorthand Operators

• iCounter iCounter 1 OR iCounter
• iCounter iCounter - 1 OR iCounter--
• iCounter iCounter 2 OR iCounter 2
• iCounter iCounter 5 OR iCounter
  5Last two examples its op then equals
  (e.g., 2), not equals then op (e.g., isnt
  2)
• These work with , -, , / plus others.
• i // means increment i
• i 2 // means add 2 to the value of i
• WARNING THESE ARE NOT JUST CUTE TRICKS THEY ARE
  VERY POWERFUL AND CAN BE MISUSED. HANDLE WITH
  CARE!!!

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Documentation Comments

• Two ways to do it
• // Double slashes comment out everything until
  the
• // end of the line
• / Starts a comment which may extend multiple
  lines and eventually be terminated by /

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Constants

• Pseudocode
• ltCONST_IDgt is ltconstant valuegt
• MIN_PASSING is 60
• PI is 3.14159
• Java
• public final static lttypegt ltIDergt ltvaluegt
• public final static int MIN_PASSING 60
• public final static float PI (float) 3.14159
• Details on why this syntax to come soon...

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