FLOWCHARTS

FLOWCHARTS

A Flowchart is a type of diagram (graphical or symbolic) that

represents an algorithm or process. Each step in the process is

represented by a different symbol and contains a short description of

the process step. The flow chart symbols are linked together with

arrows showing the process flow direction. A flowchart typically

shows the flow of data in a process, detailing the operations/steps in a

pictorial format which is easier to understand than reading it in a

textual format.

A flowchart describes what operations (and in what sequence)

are required to solve a given problem. A flowchart can be likened to

the blueprint of a building. As we know a designer draws a blueprint

before starting construction on a building. Similarly, a programmer

prefers to draw a flowchart prior to writing a computer program.

Flowcharts are a pictorial or graphical representation of a process. The

purpose of all flow charts is to communicate how a process works or

should work without any technical or group specific jargon.

Flowcharts are used in analyzing, designing, documenting or

managing a process or program in various fields.

Flowcharts are generally drawn in the early stages of

formulating computer solutions. Flowcharts often facilitate

communication between programmers and business people. These

flowcharts play a vital role in the programming of a problem and are

quite helpful in understanding the logic of complicated and lengthy

problems. Once the flowchart is drawn, it becomes easy to write the

program in any high level language. Often we see how flowcharts are

helpful in explaining the program to others. Hence, it is correct to say

that a flowchart is a must for the better documentation of a complex

program.

For example, consider that we need to find the sum, average

and product of 3 numbers given by the user.

Algorithm for the given problem is as follows:

Read X, Y, Z

Compute Sum (S) as X + Y + Z

Compute Average (A) as S / 3

Compute Product (P) as X x Y x Z

Write (Display) the Sum, Average and Product

Flowchart for the above problem will look like

Now that we have seen an example of a flowchart let us list the

advantages and limitations of using flowcharts.

Advantages of Using Flowcharts:

The benefits of flowcharts are as follows:

• Communication: Flowcharts are better way of communicating 
  the logic of a system to all concerned.
• Effective analysis: With the help of flowchart, problem can be 
  analysed in more effective way.
• Proper documentation: Program flowcharts serve as a good 
  program documentation, which is needed for various purposes.
• Efficient Coding: The flowcharts act as a guide or blueprint 
  during the systems analysis and program development phase.
• Proper Debugging: The flowchart helps in debugging process.
• Efficient Program Maintenance: The maintenance of operating 
  program becomes easy with the help of flowchart. It helps the 
  programmer to put efforts more efficiently on that part.

Limitations of Using Flowcharts:

Although a flowchart is a very useful tool, there are a few limitations

in using flowcharts which are listed below:

• Complex logic: Sometimes, the program logic is quite 
  complicated. In that case, flowchart becomes complex and 
  clumsy.
• Alterations and Modifications: If alterations are required the 
  flowchart may require re-drawing completely.
• Reproduction: As the flowchart symbols cannot be typed, 
  reproduction of flowchart becomes a problem.

• The essentials of what is done can easily be lost in the technical details of how it is done.

When to Use a Flowchart:

• To communicate to others how a process is done.
• A flowchart is generally used when a new project begins in 
  order to plan for the project.
• A flowchart helps to clarify how things are currently working 
  and how they could be improved. It also assists in finding the 
  key elements of a process, while drawing clear lines between 
  where one process ends and the next one starts.
• Developing a flowchart stimulates communication among 
  participants and establishes a common understanding about the 
  process. Flowcharts also uncover steps that are redundant or 
  misplaced.
• Flowcharts are used to help team members, to identify who 
  provides inputs or resources to whom, to establish important 
  areas for monitoring or data collection, to identify areas for 
  improvement or increased efficiency, and to generate 
  hypotheses about causes.
• It is recommended that flowcharts be created through group 
  discussion, as individuals rarely know the entire process and 
  the communication contributes to improvement.
• Flowcharts are very useful for documenting a process (simple 
  or complex) as it eases the understanding of the process.
• Flowcharts are also very useful to communicate to others how a 
  process is performed and enables understanding of the logic of 
  a process.

Flowchart Symbols & Guidelines:

Flowcharts are usually drawn using some standard symbols;

however, some special symbols can also be developed when required.

Some standard symbols, which are frequently required for

flowcharting many computer programs are shown.

Terminator : 

An oval flow chart shape indicates the start or end of the

process, usually containing the word “Start” or “End”.

Process: A rectangular flow chart shape indicates a normal/generic

process flow step. For example, “Add 1 to X”, “M = M*F” or similar.

Decision: A diamond flow chart shape indicates a branch in the

process flow. This symbol is used when a decision needs to be made,

commonly a Yes/No question or True/False test.

Connector: A small, labelled, circular flow chart shape used to

indicate a jump in the process flow. Connectors are generally used in

complex or multi-sheet diagrams.

Data: A parallelogram that indicates data input or output (I/O) for a

process. Examples: Get X from the user, Display X.

Delay: used to indicate a delay or wait in the process for input from

some other process.

Arrow: used to show the flow of control in a process. An arrow

coming from one symbol and ending at another symbol represents that

control passes to the symbol the arrow points to.

These are the basic symbols used generally. Now, the basic guidelines

for drawing a flowchart with the above symbols are that:

• In drawing a proper flowchart, all necessary requirements 
  should be listed out in logical order.
• The flowchart should be neat, clear and easy to follow. There 
  should not be any room for ambiguity in understanding the 
  flowchart.
• The flowchart is to be read left to right or top to bottom. 
• A process symbol can have only one flow line coming out of it.
• For a decision symbol, only one flow line can enter it, but 
  multiple lines can leave it to denote possible answers.
• The terminal symbols can only have one flow line in 
  conjunction with them.

Basic Flowchart

Example:

Consider another problem of finding the largest number between A and 

B

Algorithm for the above problem is as follows:

Read A, B

If A is less than B

                 BIG=B

                 SMALL = A

Else

                 BIG=A

                 SMALL = B

Write (Display) BIG, SMALL

Flowchart for the above algorithm will look like:

Types of Flowcharts:

• High-Level Flowchart:

A high-level (also called first-level or top-down) flowchart

shows the major steps in a process. It illustrates a "birds-eye view"

of a process. It can also include the intermediate outputs of each

step (the product or service produced), and the sub-steps involved.

Such a flowchart offers a basic picture of the process and identifies

the changes taking place within the process. It is significantly

useful for identifying appropriate team members (those who are

involved in the process) and for developing indicators for

monitoring the process because of its focus on intermediate

outputs.

Most processes can be adequately portrayed in four or five

boxes that represent the major steps or activities of the process. In

fact, it is a good idea to use only a few boxes, because doing so

forces one to consider the most important steps. Other steps are

usually sub-steps of the more important ones.

Given below is an example of High-Level Flowchart of an

Order Filling Process. It provides the most important steps required

in the process.

• Detailed Flowchart:

The detailed flowchart provides a detailed picture of a process

by mapping all of the steps and activities that occur in the process.

This type of flowchart indicates the steps or activities of a process

and includes such things as decision points, waiting periods, tasks

that frequently must be redone (rework), and feedback loops. This

type of flowchart is useful for examining areas of the process in

detail and for looking for problems or areas of inefficiency.

Given below is the Detailed Flowchart of an Order Filling

Process which shows the sub-steps involved in the process and also

reveals the delays that occur when the materials required are not

available in the inventory.