Basics of Flowchart – BKNMU Junagadh | BCA Sem 1 Notes
BCA Sem 1 | Unit 1 | Computer Concepts & C Programming
Basics of Flowchart — BKNMU Junagadh
Definition, Importance, Standard Symbols (Shapes), Rules, Advantages & Disadvantages
To master problem-solving in BCA, you must understand the three core aspects of flowcharting:
1. Standard Symbols
Uses uniform geometric shapes predefined by **ANSI** rules. Each shape represents a specific type of operation.
2. Flow Direction
Connects shapes to indicate the precise order and direction in which instructions are executed.
3. Decision Making
Clearly visualizes conditional logic (e.g., IF-ELSE), showing the system's choice-based paths.
Here is the definitive guide to standard flowchart symbols used in C programming logic design:
| Symbol | Shape Name | Description / Application | Flow Rule |
|---|---|---|---|
Oval | Terminal Symbol | Indicates the logical START or END point of the flowchart logic. | One flowline (In for END; Out for START). |
Rectangle | Process Symbol | Represents internal processing, calculations, or variable initialization steps. | One flowline in, one flowline out. |
Parallelogram | Input / Output Symbol | Represents instructions that read data from input or display data to output. | One flowline in, one flowline out. |
Diamond | Decision Symbol | Used for conditional checks (True/False or Yes/No) where the path splits based on a Boolean result. | One flowline in, two (or more) flowlines out. |
Small Circle | Connector Symbol | Used to connect different parts of a complex flowchart, often on the same page, to improve readability. | One flowline in, one flowline out. |
Arrows | Flowlines Symbol | Connects standard shapes to indicate the precise sequence of operations. | Connects any two standard symbols. |
The Structure of a Simple Flowchart:
Arrows must maintain a logical, single direction from START to END, typically following a top-to-bottom or left-to-right flow pattern.
Maintain Logical Flow Direction
Ensure flowlines generally move from top to bottom or left to right. Avoid unnecessary flowline crossings.
Use Standard ANSI Symbols Only
Never create custom shapes! Only use the predefined geometric shapes (Oval, Rectangle, Diamond, etc.) understood universally.
Label Decision Paths Clearly
Always label the outgoing paths from a Decision diamond with **Yes/True** and **No/False** based on the condition result.
Keep Logic Concise and Terminated
Use simple, non-syntax specific statements inside shapes. Crucially, the flowchart must always terminate at an END symbol.
- Better communication: Complex logic is easier to understand visually.
- Efficient analysis: Simplifies the debugging process by tracking logic paths.
- Effective documentation: Acts as a logical blueprint for the actual C program code.
- Debugging aid: Helps identify logical flaws before coding begins.
- Time-consuming to draw for large, complex programs.
- Difficult to modify: Changing logic often requires completely redrawing the chart.
- Complexity increases exponentially with the size of the program logic.
- Not ideal for highly recursive or parallel logic designs.
- Definition: Graphical/diagrammatic representation of an algorithm.
- Standards: Predefined ANSI standard geometric shapes are universally understood.
- Flowlines: Connect shapes to indicate logical execution sequence and direction.
- Shapes to Remember: Terminal (START/END), Process (Calculation), I/O, Decision (Branching).
- Main Goal: To visualize logic and sequence before actual C programming coding starts.
- Rule of Termination: Every valid flowchart must strictly conclude at an END symbol.