Flowcharts

A flowchart is a visual representation of a process.

Flowchart symbols are standardized, the way the text is written is not.

Flowchart Symbols

Terminator

• Oval or rounded rectangle.
• Indicates the start or end of a process.

Flow Arrow

• Arrow connecting two symbols.
• Indicates the flow of the process.

Process

• Rectangle.
• Represents a process, action, or operation.
• Also represents assignment of a value.
• Typically contains a verb.
• Examples:
  • "Calculate total"
  • "Print invoice"
  • "Add new customer"
  • "Set balance = 0"
  • "balance = 0"
  • "balance := 0"

Decision

• Represents a decision point.
• Branches to different parts of the flowchart based on a condition.
• Branches are labeled
  • "Yes" or "No"
  • "True" or "False"
• Possible ways to express a decision:
  • "Is the customer a member?"
  • "Customer is member?"
  • "Is the balance over $1000?"
  • "Balance > $1000?"

Input / Output

• Represents input or output.
• May have arrow pointing to or from the symbol.
  • Arrow connecting on the left side is input.
  • Arrow stemming from the right side is output.
• Input can be a variable assignment.

Input Example:

• "input customer name"
• "enter customer name"
• "-> customer name"
• "customer name"

Output Example:

• "print total"
• "display total"
• "output total"

Data Store

• Cylinder
• Represents a data store
  • Database
  • File

Examples and Exercises

START
    // Get the inputs
    // In a realistic example, we may have the list coming from a file or database,
    // and the user entering the target value.
    GET list
    GET target

    // current_index represents the "spot" within the list that we are currently checking
    SET current_index = 1
    // Start by assuming the target is not found
    SET found = false

    WHILE current_index <= length of list:
        IF the item at the current index is the target:
            SET found = true
        END IF

        // Move to the next item in the list
        ADD 1 to current_index
    END WHILE

    // Output the result
    IF found is true:
        PRINT "Found at index", current_index
    ELSE:
        PRINT "Not found"
    END IF
END