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Unformatted text preview: CMPT 126: Lecture 8 Object-Oriented Design Tamara Smyth, [email protected] School of Computing Science, Simon Fraser University November 13, 2007 1 Software Development Activities • When the code for your programs starts getting big, with numerous .java files, you will have to start thinking about how to manage it all. • Software development effort consists of four basic development activities 1. establishing the requirements: 2. creating a design 3. implementing the design 4. testing CMPT 126: Object-Oriented Design, Lecture 8 2 Establishing the requirements • Software requirements : – a clear expression of the programming problem – specification of what a program must accomplish often using a document called functional specification . – usually specified by a client , though often modified throughout the project in conjunction with the programmer – often address user interface issues: output format, screen layouts, GUI components, etc. – may apply constraints to your program (such as computer resources) CMPT 126: Object-Oriented Design, Lecture 8 3 Software Design • A software design : – indicates how a program will accomplish its requirements. – may deal with how methods accomplish their tasks (in a low-level design) – allows alternatives to be considered and explored (before all the effort goes into implementation). – In an object orientated design, the following is specified: * the classes and objects needed in a program * the interaction of the objects and the relationships among the classes CMPT 126: Object-Oriented Design, Lecture 8 4 Implementation • Implementation is the process of writing the source code that will solve the problem. More precisely: – the act of translating the design into a programming language – should be the “least creative” of all development activities – important decisions are already established CMPT 126: Object-Oriented Design, Lecture 8 5 Testing • Finding the bugs! • Testing is the act of ensuring that a program solves the problem successfully, given all the established constraints. • Among other things, it involves running the program several times under several different conditions, and then scrutinizing the results. CMPT 126: Object-Oriented Design, Lecture 8 6 Identifying Classes and Objects • A fundamental part of object-oriented software design is determining the classes that will contribute to the program. • These classes determine the objects that we will manage in the system. • To identify potential classes, identify objects discussed in the program requirements. CMPT 126: Object-Oriented Design, Lecture 8 7 Look for Nouns in Problem Description • Objects are generally nouns; the nouns in a problem description may indicate some of the classes and objects needed in a program....
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- Spring '08
- Object-Oriented Programming, Subroutine, reserved word, static variable, Object-Oriented Design