CPSC 320: Week 9

• Packages



• Packages allow us to define Abstract Data Types
• Data Type - set of values and operations
• Abstract - pay attention to relevant details (ie what operations are available)
• Abstract - ignore details not relevant to task at hand (ie how operations are implemented)


• Word package: specification,


• Word package: implementation,


• Example: Big numbers: Specification , and a sample program that uses it. Bignum implementation.


• Specification and client of an Integer Stack Package


• Integer Stack Package


• Program 3 : Now available


• A useful summary of Ada (but accuracy not guaranteed)
• A similar idea, comparing Ada and Java


• Reading on packages: Chapter 11 and section 3.1


• Generic Packages


• Reading on generic packages: Chapter 17 and section 3.4
  
• Terms:
  • ADT: Abstract data type: type and operations are available to client, but implementation details are not available to client
  
  
  • Interface of an ADT: Items listed in specification that are available to the client
  
  
• Another generic package: Interface for Queue ADT


• Reading on generic packages: Chapter 17 and section 3.4