Flowchart

IDT

What is a flowchart?

Visual representation of a flow of data Outline of process or a solution to a problem Outline the basic logic behind a software or

program Principal rule: one-in-one-out

Only ONE way INTO the structure Only ONE way OUT of the structure

Direction = flow of the procedure or system top to bottom left to right

Example

Borrow a book from the library with a library card:

1. Do I have my library card with me? Yes - proceed to next step. No - find my library card.

2. Go to library.

3. Search for a book.

4. Sign out the book.

Basic Flowchart Symbols

Symbol Name Function

Start/End Shows the beginning and end of the system or process

Process An action done by the program (e.g. calculate the area of a square)

Arrows Shows the direction and sequence of processes

Decision Asks a question and then determines which route the program will take

Basic Flowchart Symbols

Symbol Name Function

Input/Output

Represents when something is input into the program or output from the program

Connector Connects one part of the flowchart to another part of the flowchart on the same page using matching symbols

Off-page Connector

Connects one part of the flowchart to another part of the flowchart on a different page using matching symbols

Sequence Control Structure

• All actions must be executed

• Only one way to enter this sequence structure (at the start)

• Only one way to exit the structure (at the end)

• What is the output?

Decision or Selection Control Structure

• Only one way to enter the program

• Only one way to exit the program - even though there are several possible paths to take once you come across a decision (the diamond symbols)

• Which action to take is based on a certain condition

• What is the output?

Repetition or Loop Control Structure

• Do While or do until

• What is the output?

Sum of First 50 natural numbers

Sample Flow Charts

Decision/Selection Structure

Sample Flow Charts

Let’s practice

You want to buy a computer that will cost $2000. You don’t have the money yet, but you plan to save $100 each month toward the purchase. Create a flow chart using selection/decision and repetition.

Computer Purchase Flow Chart

Assignment

Select an everyday activityCreate a decision/selection flow chart for

the activity. Use the correct shapes for start/end, direction, process, decisions, etc.