Methods Part 2: The Hokey Pokey Example

Methods Part 2

• Methods are used to perform actions
• A method sends a message to an object or class
• To build a method in Alice, click "create new method"
• Then drag statements into the method
• Students have likely created main methods and other methods before
• Example: The Hokey Pokey Song
  • Brute force: store song lyrics in a single string, display in one action, 60 lines of code (excessive)
  • Better approach: leverage song structure, single method ("printVerse") takes a "bodyPart" argument
  • This example shows how a method can streamline code

Method Example: The Hokey Pokey Song Lyrics

• Detailed Hokey Pokey lyrics provided, including all verses.

Introductory Example: The Hokey Pokey Song (Continued)

• HokeyPokey.java to display Hokey Pokey lyrics properly.
• Code example demonstrating a printVerse method, taking a "body part" parameter. This correctly illustrates efficiency.

Methods (Continued)

• Analyzing printVerse method
  • public: accessible by other classes
  • static: a class method, not specific to an object
  • void: does not return a value (unlike a function which does return a value).
  • printVerse: the methods' name
  • (): parameter list, String bodyPart
  • {}: containing the method's statements/actions.
• Shows a simplified Java method structure
  • [AccessMode] [static] ReturnType MethodName (Params) {Statements}

Non-void vs. void Methods

• Alice methods:
  • Methods: just run statements
  • Functions: return a value
• Java considers both methods
• void method in Java:
  • Corresponds to an Alice method (no return type)
• non-void method in Java:
  • Corresponds to an Alice function (requires a return type)

Einstein's Formula

• e = m x c²: energy = mass x speed of light²
  • Formula itself could be a user story
• massToEnergy method example
  • Method returns a double
  • Parameter list includes a double mass
  • SPEED_OF_LIGHT is a constant outside the method
  • Calculation is within the return statement

Einstein's Formula (Continued)

• Code example of the massToEnergymethod, using the formula
• Shows how a method can encapsulate a complex calculation.
• Returns a computed double value

Explore the concept of methods in programming with a focus on the Hokey Pokey song example. Learn how to create efficient methods to streamline code and analyze the structure of the printVerse method. This quiz will test your understanding of method creation and implementation.