Algorithm Design - Flowchart from Pseudo-code

Objective

To learn how to draw a flowchart based on a given set of pseudo-code instructions.

Understanding Flowcharts

A flowchart is a diagram that illustrates the steps involved in solving a problem. It uses standard symbols to represent different types of operations and the flow of control.

Common Flowchart Symbols

Symbol	Description
Start/End	Oval - Indicates the beginning and end of the algorithm.
Process	Rectangle - Represents a step or operation.
Decision	Diamond - Represents a point where a decision is made.
Input/Output	Parallelogram - Represents input or output operations.
Connector	Circle - Used to connect different parts of the flowchart.
Predefined Process	Rectangle with double lines - Represents a sub-routine or predefined process.

Example Pseudo-code

Consider the following pseudo-code algorithm to calculate the area of a rectangle:

    START
    INPUT length, width
    IF length > 0 AND width > 0 THEN
        area = length * width
        OUTPUT area
    ELSE
        OUTPUT "Invalid input: Length and width must be positive."
    ENDIF
    END
    

Flowchart Representation

Here's the flowchart representation of the above pseudo-code:

1. Start (Oval)
2. Input length, width (Parallelogram)
3. Decision: length > 0 AND width > 0 (Diamond)

4. If Yes:

5. area = length * width (Process)
6. Output area (Parallelogram)

7. If No:

8. Output "Invalid input..." (Parallelogram)
9. End (Oval)

Explanation

The flowchart visually represents the flow of control in the algorithm. It shows the input steps, the decision point, the calculation process, and the output steps. The connectors indicate the flow of execution.