What is Flow Chart?
The flow process chart was
basically introduced by Frank Gilbreth in 1921 as a well defined structured
method for presenting the process flow, in his presentation “Process Charts, The
First Steps was to Find the Best Way to Do Work.”. Later on he
first design of flowchart goes back to 1945 which was structured and designed by
John Von Neumann. Unlike an algorithm, Flowchart uses various symbols for
presenting a solution of a problem.Flowchart
is diagrammatic /Graphical representation of sequence of steps to solve a
problem.
Advantages Of Flowchart.
1) It's
a convenient method of communication.
2) It indicates very clearly just
what's being done, where a program has
logical complexities.
3) A key to correct programming.
4) It's
a very important tool for planning and designing
a brand new system.
5) It clearly indicates the role-played at each level.
6) It saves the inconveniences in future and serves
the aim of documentation
for a system.
7) It provides
an summary of the system and also demonstrates
the
connection between various steps.
8) Facilitates troubleshooting.
9) It promotes logical accuracy.
10) It makes sure that no logical path is left incomplete
without any action
being taken.
Disadvantages Of Flowchart
1) The flowchart
could be a waste
of your time and slows down
the method of software development.
2) The flowchart
is sort of costly
to produce and difficult to use and manage.
3) Flowcharts
don't seem to be meant for man to computer communication.
4) Sometimes the Complex logic of the program logic
is quite complicated to
draw out on by using different defined shapes.
in that case, flowchart becomes complex and clumsy.
this can become a pain for the user,
resulting in a waste
of your time and money trying to correct
the problem
5) If
you would like
to modify or alternate
the process then
it'll be very hard
to do
within the flowchart. Because either
you may
have to erase
the end of the flowchart or start.
To draw a flowchart following standard symbols are use
1) Terminator
The terminator symbol represents the starting or ending point of the system.
2) Process
A box indicates some particular operation.
3) Document
This represents a printout, such as a document or a report.
4) Decision
A diamond represents a decision or branching point. Lines coming out from the diamond indicates different possible situations, leading to different sub-processes.
5) Data
It represents information entering or leaving the system. An input might be an order from a customer. Output can be a product to be delivered.
6) On-Page Reference
This symbol would contain a letter inside. It indicates that the flow continues on a matching symbol containing the same letter somewhere else on the same page.
7) Off-Page Reference
This symbol would contain a letter inside. It indicates that the flow continues on a matching symbol containing the same letter somewhere else on a different page.
8) Delay or Bottleneck
Identifies a delay or a bottleneck.
9) Flow
Lines represent the flow of the sequence and direction of a process.
The language used to write algorithm is simple and similar to day-to-day life language. The variable names are used to store the values. The value store in variable can change in the solution steps. In addition some special symbols are used as below
Assignment Symbol ( <-- or =) is used to assign value to the variable. e.g. to assign value 5 to the variable HEIGHT, statement is
HEIGHT <-- 5 or HEIGHT=5
The symbol ‘=’ is used in most of the programming language as an assignment symbol, the same has been used in all the algorithms and flowcharts in the manual.
The statement C=A+B means that add the value stored in variable A and variable B then assign/store the value in variable C.
The statement R=R+1 means that add I to the value stored in variable R and then assign/store the new value in variable R, in other words increase the value of variable R by 1
| Operator | Meaning | Example |
| + | Addition | A +B |
| - | Subtraction | A -B |
| * | Multiplication | A * B |
| / | Division | A / B |
| ^ | Power | A^3 for A power 3 |
| % | Reminder | A % B |
Relational Operators
| Operator | Meaning | Example |
| < | Less than | A < B |
| <= | Less than or equal to | A<=B |
| = or == | Equal to | A = B |
| # or != | Not equal to | A # B or A !=B |
| > | Greater than | A > B |
| >= | Greater than or equal to | A>=B |
Logical Operators
| Operator | Example | Meaning |
| AND | A<B AND B<C | Result is True if both A<B and B<C are true else false |
| OR | A<B OR B<C | Result is True if either A<B or B<C are true else false |
| NOT | NOT (A>B) | Result is True if A>B is false else true |
Selection control Statements
| Selection Control | Example | Meaning |
|
IF ( Condition ) Then ....... END IF |
IF (X>10) THEN Y=Y+5 END IF |
If condition X> 10 is True execute the statement between THEN and END IF |
|
IF ( Condition ) Then ....... ELSE ....... |
IF (X>10)THEN Y=Y+5 ELSE Y=Y+8 Z=Z+3 |
If condition X>10 is True execute the statement between THEN and ELSE otherwise execute the statements between ELSE and END IF. |
Loop control Statements
| Selection Control | Example | Meaning |
| WHILE (CONDITION) DO ...... ...... END DO |
WHILE(X<10) DO PRINT X X=X+1 END DO |
Execute the loop as long as the condition is TRUE |
| DO ...... UNTIL (CONDITION) |
DO PRINT X UNTIL (X>10) |
Execute the loop as long as the condition is FALSE
|
GOTO statement also called unconditional transfer of control statement is used to transfer control of execution to another step/statement. . e.g. the statement GOTO n will transfer control to step/statement n.
Note: We can use keyword INPUT or READ or GET to accept input(s) /value(s) and keywords PRINT or WRITE or DISPLAY to output the result(s).
