Why Flowchart

1
Why Flowchart?

• Lets explore the reasons we should flowchart.

2
Its a graphic representation of the algorithm

• A flowchart shows the flow of processing from the
  beginning to the end of the solution.
• It is the single most important step in
  organizing a solution to the problem.
• Instructions in a flowchart symbol are generic
  rather than specific to any particular language.

3
Errors

• Logic errors can be identified much more easily
  in a flowchart than in actual code.
• You can test the algorithm prior to writing code.
  
• After the programmer has spent hours writing code
  is no time to discover a logic problem that may
  force him to return to the very beginning of
  program design - the flowchart.

4
Terminal Symbol

• Indicates the start and end of a function.
• Use the word end or stop for the Main Function.
• Use begin and the function name.
• Use the words exit or return for all other
  functions.

Start
End
5
Processing

• Used to indicate any kind of processing such as
  calculations, copying data, incrementing
  counters, etc.

A BC
6
Input/Output

• Indicates input to and output from the computer
  memory.
• Some words that are used here include READ,
  INPUT, SCAN, DISPLAY, PRINT, GET, WRITE, ACCEPT.

GET length of room in inches.
7
Decision Statement

• Indicates a logical (TRUE or FALSE).
• It should have only 1 entrance and only 2 exits.
• Put the question in the box and show the
  direction of the decisions.

Install?
yes
no
8
Predefined Process

• Represents a function and is placed in the
  calling function.
• A function has only 1 entrance and 1 exit.
• The name of the function should be used in the
  start terminal symbol.

Dimensions
Begin Dimensions
9
Loop Control
Initialize B

• Represents a loop with a counter.
• The counter starts with B (the beginning value),
  is incremented by S (the incrementing value),
  until the counter is greater than E (the ending
  value).

BBS
Is BgtE?
no
yes
10
Page Connectors

• The circle connects sections on the same page.
• The plate connects flowcharts from page to page.
• Letters or numbers are written inside to connect
  to a corresponding letter or number in a
  different area.

A
B
11
The Sequence Structure
12
The Double Decision Structure
13
The Single Decision Structure
14
The Repeat-Until Structure
15
The While Structure
16
The Case Structure
17
Lets Flowchart
Write a program to calculate the cost of carpet
for a room. Get dimensions of the room from the
user. Allow the user to choose from three
different carpets. The price of the given
carpets are per square foot. Charge 8 tax. If
they want installation add 0.50 per square foot.
Display all information known for the customer
to see.