Flowcharts: Visual representations of the steps involved in an algorithm.
Algorithm: A set of instructions designed to solve a problem.
Flowcharts are used both in real life and computing, providing a visual way to understand processes.
Main Flowchart Symbols
Start/End Symbol
Indicates beginning or end of a flowchart.
Represented by an oval shape with 'Start' or 'End'.
Process Symbol
Represents an action or step in the algorithm.
Shown as a rectangle with a brief description of the process.
Input/Output Symbol
A parallelogram shape indicating input or output operations.
Used specifically to show operations that require user input or display an output.
Decision Symbol
Diamond shape used to pose a question that has a binary answer (Yes/No).
Requires two pathways for the possible answers, guiding the next steps in the flowchart.
Example Flowchart Explanation
Scenario: A login process for a website.
Flowchart Steps:
Start by checking if the user has an account.
If no account, direct to sign up screen and loop back to check again.
If account exists, prompt for username and password.
Verify account details:
If incorrect, loop back for re-entry.
If correct, proceed to success and end the program.
Describes the process of authenticating a user.
Important Points:
Use arrows to indicate the direction of flow.
Ensure every arrow has a clear head to show direction.
It's common to loop back in flowcharts to repeat certain steps.
Special Flowchart Symbols
Subroutine Symbol: A rectangle with two additional lines.
Indicates a separate flowchart or program.
Useful for breaking down complex processes into simpler parts.
Example of subroutine: A separate flowchart for a 'Sign Up' process involving entering username and password, checking for existing users, and saving new user details if no duplicates exist.
Key Takeaways
Ability to draw simple flowcharts and know the meaning of each symbol is crucial.
Interpretation of flowcharts is important for understanding processes and algorithms.
Techniques like using subroutines or breaking up complex processes can simplify flowchart creation and understanding.