1. 1 STRUCTURE CHARTS An Example: The Registration System

2. 2 registration system read & check registration compute registration produce registration outputs reg+ invoice conf reg+ conf invoice 0 12 3

3. 3 registration system read & check registration compute registration produce registration outputs reg+ invoice conf reg+ conf invoice 0 1 2 3

4. 4 read & check registration reg_i 1 read registration 1.1 check registration 1.2 error-handler registration 1.3 reg_i reg_flag error_reason CRT registration error-msg

5. 5 registration system read & check registration compute registration produce registration outputs reg+ invoice conf reg+ conf invoice 0 12 3

6. 6 compute registration invoice 2 prepare invoice 2.1 accept registration 2.2 reg+ registration db reg_info conf reg+ prices reg_profile

7. 7 registration system read & check registration compute registration produce registration outputs reg+ invoice conf reg+ conf invoice 0 1 2 3

8. 8 produce registration outputs 3 print invoice 3.1 write confirmation 3.2 conf CRT conf_msg invoice invoice_prt PRT

9. 9 0 1 23 1.11.21.32.12.23.13.2 crtdbprtcrt input-drivenoutput-driven center of transformation

10. 10 Remember during Composition a module is a unit of execution invocation between modules is directed data flows and control flows must follow the invocation hierarchy data stores, devices, and external systems are typically at the lowest level of your SC sequence of execution depends on the internal specification

11. 11 Suggestions for a Good Style have a balanced system: input => processing => output think in terms of stepwise-refinement module encapsulates a single function limit the use of control flows reflect the sequence of execution in your SC

12. 12 A Structure Chart is derived from a Data Flow Diagram and is a mapping and refinement of the DFD. ==> Algorithms? / Heuristics? DFD SC ????

13. 13 End of Section 3c coming up: DFDs SCs