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The Model-View-Controller Paradigm

Separating concerns between the Model, View, and Controller​

Our programs are getting large and complicated. We like to organize our code by separating it into "categories."

The Model

  • The Model should contain all classes related to the functionality of a program. Most classes that we have written so far this semester belong in the Model category.
  • The Model should not care about what functionality is needed when
  • The Model should not depend on the controller calling its methods in a certain order
  • The Model should not care when / how results are shown to user

The View

  • Displays results to user
  • Should not care how results were calculated
  • Should not directly respond to user actions

The Controller

  • The Controller takes user inputs
  • The Controller tells the model what to do, tells view what info to display
  • The Controller should not care how the model implemented the functionality
  • The Controller should not care how results are displayed
  • The Controller is the only one that can talk to the model and view (Model and view cannot directly talk to each other)

Images

Examples

Designing the Model​

Tic Tac Toe model