Structure chart is a chart derived from Data Flow Diagram. It represents the system in more detail than DFD. It breaks down the entire system into lowest functional modules, describes functions and sub-functions of each module of the system to a greater detail than DFD.
Structure chart represents hierarchical structure of modules. At each layer a specific task is performed.
Here are the symbols used in construction of structure charts –
- Module – It represents process or subroutine or task. A control module branches to more than one sub-module. Library Modules are re-usable and invokable from any module.
- Condition – It is represented by small diamond at the base of module. It depicts that control module can select any of sub-routine based on some condition.
- Jump – An arrow is shown pointing inside the module to depict that the control will jump in the middle of the sub-module.
- Loop – A curved arrow represents loop in the module. All sub-modules covered by loop repeat execution of module.
- Data flow – A directed arrow with empty circle at the end represents data flow.
- Control flow – A directed arrow with filled circle at the end represents control flow.