Coupling

• A class depends on another if it uses objects of that class

• CashRegister depends on Coin to determine the value of the payment

• Coin does not depend on CashRegister 
  since none of the coin operations require the CashRegister class.
   

• High Coupling = many class dependencies

• Minimize coupling to minimize the impact of interface changes

• To visualize relationships draw class diagrams

UML: Unified Modeling Language. Notation for object-oriented analysis and design