1. Software Development
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2. “Good” Software
When developing software, we strive for software that is
correct (meets requirements)
reliable (bug-free)
easily maintained (corrections and upgrades)
reusable
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3. An OO approach to software looks at the problem in terms of “things”
Procedural vs. OO
A procedural approach to software looks at the problem in terms of functionality
An OO approach to software looks at the problem in terms of “things”
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4. Software Development Life Cycle
Five phases:
Requirements Analysis
Design
Implementation
Testing
Maintenance
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5. Software Development Life Cycle (cont’d)
Requirements Analysis Phase
Formally specify (document) what the problem is
Make sure that you and the “client” agree
Develop system test cases
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6. Software Development Life Cycle (cont’d)
Design Phase
Formally specify (document) how the problem is to be solved
Make sure that the design conforms to the requirements (i.e., it will produce what was specified in the analysis phase)
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7. Example – The game of Chess
Procedural – what are the rules?
OO – what chess pieces are there and how do they move?
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8. OO – envision chess pieces and board and their attributes
More Chess
Procedural – envision a 2-D matrix for the board and functions that move a piece from one square to the next
OO – envision chess pieces and board and their attributes
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9. Software Development Life Cycle (cont’d)
Implementation Phase
Convert the design to code
Procedural -- functions
OO -- objects
Compile and remove all syntax errors
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10. Software Development Life Cycle (cont’d)
Testing Phase
Unit Testing: Test each unit (e.g., function, object) for logic errors and make corrections
Procedural – function test driver
OO – object test driver
System Testing: Test the entire program to make sure that it conforms to the requirements
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11. Software Development Life Cycle (cont’d)
Maintenance Phase
Fix bugs found by the customer
Make modifications ($$!)
Add new features ($$!)
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12. So How Does the S/W Life Cycle Apply to My Projects?
Follow the first four phases, but anticipate the last (Maintenance)
Complete the Analysis
Complete the Design
Do a combination of Implementation and Testing
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