Structured design methodology: which primary tool is used to represent the modular decomposition and calling relationships in a design?

Introduction / Context:
Structured analysis and structured design are distinct phases with different tools. Analysts frequently confuse data-flow diagrams (analysis) with structure charts (design). Knowing which artifact fits which phase improves communication and maintainability.

Given Data / Assumptions:

• We are in the design phase (not analysis).
• We need a representation of modules, hierarchy, and interfaces.

Concept / Approach:
A structure chart shows modules, their calling relationships, parameters, and control/data coupling. It is the canonical tool for structured design. By contrast, a data-flow diagram models the movement and transformation of data in structured analysis.

Step-by-Step Solution:

Verification / Alternative check:
Classic methodologies (e.g., Yourdon/DeMarco) pair DFDs for analysis and structure charts for design handoff.

Why Other Options Are Wrong:
DFDs are analysis tools; program flowcharts focus on control flow, not modular architecture; “module” alone is not a diagrammatic tool.

Common Pitfalls:
Over-coupled designs and missing parameter specifications on the chart; always minimize coupling and maximize cohesion.

Final Answer:
Structure chart