Lecture 08
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The document discusses tabular structures and data flow diagrams. It provides an example of using a table to clearly show income tax rates based on taxable income levels. Tabular structures make information easier to understand. A data flow diagram captures how data moves through a system by showing the sources, transformations, and outputs of data. It helps develop an understanding of a system's functionality at different levels of abstraction.
Lecture 08
- 1. Lecture 08
- 2. Tabular Structures Sometimes it is better and more convenient to arrange information in a tabular form. This makes it easier for the reader to understand and comprehend the information and hence designing, coding, and testing become less challenging.
- 3. Tabular Method Example If the taxable income is less than Rs. 60,000, there will be no income tax. If the income exceeds Rs. 60,000 but is less than Rs. 150,000 then income tax will be charged at the rate of 7.5% for income exceeding Rs. 60,000. If the income exceeds Rs. 150,000 but does not exceed Rs. 300,000 then the income tax will be computed at 12.5% of the amount exceeding Rs. 150,000 plus Rs. 6,750. If the income exceeds Rs. 300,000 but does not exceed Rs. 400,000 then the income tax will be computed at 20% of the amount exceeding Rs. 300,000 plus Rs. 25,500. If the income exceeds Rs. 400,000 but does not exceed Rs. 700,000 then the income tax will be computed at 25% of the amount exceeding Rs. 400,000 plus Rs. 45,500. If the income exceeds Rs. 700,000 then the income tax will be computed at 35% of the amount exceeding Rs. 700,000 plus Rs. 120,500.
- 4. Income Tax Less than Rs. 60,000 0% Between Rs. 60,000 and Rs. 150,000 7.5% of (Income - 60,000) Between Rs. 150,000 and Rs. 300,000 12.5% of (Income - 150,000) + 6,750 Between Rs. 300,000 and Rs. 400,000 20% of (Income - 300,000) + 25,500 Between Rs. 400,000 and Rs. 700,000 25% of (Income - 400,000) + 45,500 Greater than Rs. 700,000 35% of (Income - 700,000) + 120,500 Tabular Method Example
- 5. Captures the flow of data in a system. It helps in developing an understanding of system’s functionality. What are the different sources of data, what different transformations take place on data and what are final outputs generated by these transformations. It describes data origination, transformations and consumption in a system. Information is organized and disseminated at different levels of abstraction. Thus this technique becomes a conduit for top down system analysis and requirements modeling. Data Flow Model
- 6. DFD – The Notation
- 7. DFD Flow Charts • Processes on a data flow can operate in parallel. • Looping and branching are typically not shown. • Each process path may have a very different timing. • Processes on flowcharts are sequential • Show the sequence of steps as an algorithm and hence looping and branching are part of flowcharts. DFD versus Flow Charts