chapter%208%20end%20of%20chapter%20questions

chapter%208%20end%20of%20chapter%20questions - Chapter 8...

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Chapter 8 Structuring System Logic Requirements Answers to Key Terms Suggested answers are provided below. These answers are presented top-down, left to right. 5. Indifferent condition 1. Action stubs 3. Decision table 2. Condition stubs 7. Structured English 4. Decision tree 6. Rules Answers to Review Questions 1. The purpose of logic modeling is to show the rules that govern the behavior of processes represented in data flow diagrams. Structured English, decision tables, and decision trees model decision logic. State diagrams model temporal logic and are discussed in Appendix 3. 2. Structured English is a modified form of the English language used to specify the logic of information system processes. Sequence is represented by listing statements at the same level of indentation. Conditional statements are represented by BEGIN IF/END IF statements and by case statements. Repetition is represented by DO. ..UNTIL and DO… While statements. 3. Although Structured English resembles spoken English, pseudocode resembles a programming language. Pseudocode is used as a communication tool between analysts and programmers, and Structured English is used as a communication tool between analysts and users. 4. The steps for creating a decision table are: (1) name the conditions and the values each condition can assume; (2) name all possible actions that can occur; (3) list all possible rules; (4) define the actions for each rule; and (5) simplify the decision table. To reduce the size and complexity of a decision table, use separate, linked decision tables, use numbers that indicate sequence rather than Xs where rules and action stubs intersect, and simplify the table by identifying indifferent conditions. 5. Decision trees are organized in a hierarchical fashion, starting with the root node on the far left, and proceeding to subsequent decision nodes. All possible actions are listed in leaf nodes on the far right. 6. You can use the tool you understand best and prefer; however, you should also consider the appropriateness of the tool for the specific situation. For example, some research shows 107
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Modern Systems Analysis and Design, 4 th edition Instructor’s Manual decision trees are best for determining the correct conditions and actions from a description of a problem. Structured English was found to be best at converting conditions and actions to sequential statements. However, Structured English is not as easy to validate as decision tables and decision trees. Decision tables are better than decision trees at portraying complex logic, are more compact, and are easier to manipulate. Decision trees are better than decision tables at portraying simple problems and at helping people make decisions in practice. 7. Structured English uses action verbs, such as read, write, print, sort, move, merge, add, subtract, multiply, and divide. Unlike regular English, Structured English does not use adjectives or adverbs.
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chapter%208%20end%20of%20chapter%20questions - Chapter 8...

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