Software Engineering for Students A Programming Approach

136 Chapter 10 ■ Data structure design
Summary
The basis of the data structure method is that the structure of a program can be
derived from the structure of the files that the program uses. The method uses a diagrammatic
notation for file and program structures. Using these diagrams, the method
proceeds step by step from descriptions of the file structures to a pseudo-code design.
The steps are:
1. draw a diagram (a data structure diagram) describing the structure of each of
the files that the program uses.
2. derive a single program structure diagram from the set of data structure
diagrams.
3. write down the elementary operations that the program will have to carry out.
4. associate the elementary operations with their appropriate positions in the program
structure diagram
5. transform the program structure diagram into pseudo-code.
In some cases, a problem exhibits an incompatibility between the structures of
two of its inputs or outputs. This is known as a structure clash. The method incorporates
a scheme for dealing with structure clashes.
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Exercises
10.1 Design a program to display a multiplication table such as young children use. For
example, the table for numbers up to 6 is:
1 2 3 4 5 6
1 1 2 3 4 5 6
2 2 4 6 8 10 12
3 3 6 9 12 15 18
4 4 8 12 16 20 24
5 5 10 15 20 25 30
6 6 12 18 24 30 36
The program should produce a table of any size, specified by an integer input from a
text box. (The structure of the input is irrelevant to this design.)
10.2 A data transmission from a remote computer consists of a series of messages. Each
message consists of:
1. a header, which is any number of SYN bytes