What is Flowchart|Flowchart symbols|Limitations|Guidelines |Examples

Definition of Flowchart

Flowchart is the combination of two words which are ‘Flow’ and ‘Chart’. A charts consists of different symbols which display the information about any program and Flow indicates the direction of processing that information which takes place in a program.

Flowchart is the graphical representation of an algorithm. It indicates a way of visually presenting the flow of data, operations which are performed on that data and sequence of these operations. Flowchart is similar as layout plan of a building. As a designer of buildings draws a layout plan of the building before constructing it similarly a programmer designs the flowchart of a program before writing that program. It is designed according to defined rules and principles.

Symbols of Flowchart

Following are the symbols which are used to design a Flowchart:

For Input/Output:

Parallelogram symbol is used to represent an input or output step.

 Process:

Rectangle symbol is used to represent a process step in flowchart.

    Selection:

Diamond symbol is used to represent a selection step. Condition is written in the diamond and flow of control from diamond symbol may go in two directions. One direction if the condition is true and one direction if the condition is false.

                                                                                                                                                                                                                                    

Start/End:

Oval symbol is used to represent the start and end step of the flowchart.

                                                                                                                                                                                                                             

Flow Lines:

Arrow symbols are used to represent the direction of flow in the flowchart. There are four types of flow lines which are used and these are following:

                                                                                                                                       

 Connector:

To combine two or more flow lines circle symbol is used. When two or more symbols come from different directions and move to one direction then connector (circle) is used.

Function call:

To call a function, rectangle symbol with double lines on left and right is used. The name of that function which we have to call is written inside the symbol with their parameters.

 

 Preparation:

This symbol is used with for loops to specify start and stop conditions.

 

 Guidelines for Drawing Flowchart

1.      Guidelines for drawing a good flowchart are following:

2.      Flowchart should be neat and clean and easy to follow.

3.      All requirements should be listed in a logical order while drawing a flowchart.

4.      The usual direction of flowchart is from top to bottom or from left to right.

5.      Only one line should come out from process symbol.

6.      Just one line should enter a decision symbol and two lines should come out of decision symbol, one for each possible answer.

7.      Just one line is used with oval symbol.

8.      Start and end of flow chart must be logical.

9.      Comments should be written in remarks symbol.

 

If the flowchart becomes complex then connector is used to reduce the flow lines.

1.  It is useful to check the validity of flowchart by using the sample data.

Limitations of Flowchart

Followings are two limitations of flowchart:

1.      To draw flowcharts for complex problems is difficult.

2.      If any change is required, flowchart has to be redesigned.

Why we use Flowcharts

1.      It is used to develop understanding that how a process is done.

2.      To study a process for improvements.

3.      It is used when better communication is needed between people involved with the same process.

4.      When we have to planning a project

5.      It is used to document a process.

Examples of Flowchart:

Example 1

Following flow chart represent the steps for adding two numbers.

   

     Example 2

The following flowchart represents the steps of an algorithm that inputs marks of a student. If marks are 40 or more, it display “pass”, otherwise it display “fails”

 Uses of Flowchart

Some basic purposes to use flowcharts are followings:

1.      It is used to show the steps of an algorithm with an easy way.

2.      It is used to understand the flow of the program.

3.      Flowchart is used to improve the logic for solving a problem.

4.      Using flowchart program can be viewed and debugged easily.

5.      It is used to represent an algorithm in simple graphical manners.