COMP 110 Designing and Overloading Methods

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COMP 110Designing and Overloading Methods

• Tabitha Peck M.S.
• March 26, 2008
• MWF 3-350 pm
• Philips 367

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Announcements
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Questions?
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Today in COMP 110

• Math Methods
• Designing Methods
• Overloading Methods

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Math Methods

• abs(double n), returns double
• ceil(float n), returns double
• floor(double n), returns double
• max(int n1, int n2), returns int
• min(float n1, float n2), returns float
• round(float n), returns int

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abs(double n)
public static double abs(double n) if ( n lt 0
) return ( n -1 ) else return n
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ceil(float n)
public static double ceil(float n) return
(double) ((int) n 1)
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min(float n1, float n2)
public static float min(float n1, float n2) if
( n1 lt n2 ) return n1 else return n2
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Design

• How would you design a video game?

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Top-Down DesignDivide and Conquer

• Big Problem
• Break problem into smaller subtasks
• Break big subtasks into smaller subtasks
• Solve subtasks to solve big problem

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Testing

• Subtasks Methods
• If a subtask doesnt work, your solution isnt
  right
• Test EVERY method you write

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Driver programs

• Simple program (for only you)
• Call methods with different inputs
• Positive, negative, zero
• True and false
• Strings, characters

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Bottom-Up Testing
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Driver Program

• setMouth(true)
• setMouth(false)
• setNoseSize(-3)
• setNoseSize(2)
• setNoseSize(10)

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Overloading

• Using the same method name for two or more
  methods within the same class
• Parameter lists are different
• average(double n1, double n2)
• average(double n1, double n2, double n3)
• Java knows what to use based on the number and
  types of the arguments

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Overloading

• Change number of arguments
• Change argument types
• Cannot change only return type

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Friday

• Lab 6