Simple
Definitions:
Algorithm:
“A step by step procedure to solve any problem is called algorithm.”
Flowchart
: “ A pictorial representation / form of algorithm is called Flowchart.”
Computer
Program: The set of instruction written in a language which computer can
understand is called computer program. Whenever you wish to write a computer
programs then the main steps are as follows:
Algorithm
: Creating an Algorithm
Flowchart
: Drawing a flowchart based on Algorithm
Program
: Converting a flowchart into a computer program.
Algorithm
:
A
step by step procedure to solve any problem is called algorithm. An
algorithm is a representation of a solution to a problem. The Algorithm is
invented by Abu Ja’far Mohammed ibn Musa Al-Khawarizmi in the 9th century. The
word is derived from the phonetic pronunciation of the last name of Mohammed
ibn Musa Al-Khawarizmi, who was an Arabic mathematician who invented a set of
rules for performing the four basic arithmetic operations on decimal numbers.
It
is commonly used for data processing, calculation and other related computer
and mathematical operations. An algorithm is also used to manipulate data in
various ways, such as inserting a new data item, searching for a particular
item or sorting an item.
To
make a computer do anything, you have to write a computer program. (A computer
program is a set of instruction given to the computer.) To write a computer
program, you have to tell the computer, step by step, exactly what you want it
to do. The computer then "executes" the program, following each step
mechanically, to accomplish the end goal.
When
you are telling the computer what to do, you also get to choose how it's going
to do it. That's where computer algorithms come in. The algorithm is the basic
technique used to get the job done. Let's follow an example to help get an
understanding of the algorithm concept.
Example1:
Making
Tea Algorithm:
Step
1: Take a container or Vessel
Step
2: Put Ingredients such as Milk, sugar, tea etc.
Step
3: Boil it
Step
4: Serve the Tea
Making
a cup of Tea by using kettle
Step
1: Fill the kettle with water.
Step
2: Switch on the power to heat the water.
Step
3: Check for boiling water. If not, go back to Step 2.
Step
4: Put all the ingredients to make tea.
Step
5: Switch off the power.
Example2:
Let's
say that you have a friend arriving at the airport, and your friend needs to
get from the airport to your house. Here are four different algorithms that you
might give your friend for getting to your home:
The
taxi algorithm:
Step
1: Go to the taxi stand.
Step
2: Get in a taxi.
Step
3 : Give the driver my address.
The
call-me algorithm:
Step
1: When your plane arrives, call on my cell phone.
Step
2: Meet me outside baggage claim area.
The
rent-a-car algorithm:
Step
1: Take the shuttle to the rental car place.
Step
2: Rent a car.
Step
3: Follow the directions to get to my house.
The
bus algorithm:
Step
1: Outside baggage claim, catch bus number 70.
Step
2: Transfer to bus 14 on Main Street.
Step
3: Get off on Elm street.
Step
4: Walk two blocks north to my house.
All
four of these algorithms accomplish exactly the same goal, but each algorithm
does it in completely different way. Each algorithm also has a different cost
and a different travel time. Taking a taxi, for example, is probably the
fastest way, but also the most expensive. Taking the bus is definitely less
expensive, but a whole lot slower. You choose the algorithm based on the
circumstances.
Flowcharts:
The
pictorial or graphical representation or form of an algorithm is called
Flowchart. Flowchart is invented by Frank Gilbreth in 1921.
A
flowchart is a type of diagram that represents an algorithm, workflow or
process. The flowchart shows the steps as boxes of various kinds, and their
order by connecting the boxes with arrows. This diagrammatic representation
illustrates a solution model to a given problem. Flowcharts are used in
analyzing, designing, documenting or managing a process or program in various
fields.
Flow charting is a tool developed in the computer industry, for showing the steps involved in
a process. The first structured method for documenting process flow, the “flow
process chart,” was introduced by Frank Gilbreth to members of American Society
of Mechanical Engineers (ASME) in 1921 as the presentation “Process
Charts—First Steps in Finding the One Best Way.”
There
are various professional softwares are available on the web which are used to
draw flowchart.
Some popular software are:
1) Microsoft Word,
2) Smart Draw,
3) Microsoft
Visio,
4) Edraw Max,
5) Google Drawings,
6) Creately,
7) yEd etc
Symbols
used in Flow Chart:
Start
/ End:
The
terminator symbol marks the starting or ending point of the system. it usually
contains the word "Start" or "End"
Process:
A
Box or Rectangle can represent a single step such as Sum = A + B
Input
/ Output:
It
represent material or information entering or leaving the system, such as Read
A, Read B
Decision:
A
decision or branching point. Lines representing different decisions emerge from
different points of the diamond.
Flow
Line:
A
Flow line indicate the sequence of the steps and the direction of flow.
Guidelines
to draw a flowchart:
The
flowchart should be neat, clean and easy to follow.
The
usual direciton of the flow of a procedure or system (Arrow) is from left to
right or top to bottom.
Only
one flow line should come out from a process symbol.
For
Example:
Only
one flow line should enter a decision symbol.
Ensure
that the flowchart has a logical start and finish.
Converting
Algorithm to a Flowchart:
Flowchart
based on a algorithm to find the sum of two numbers
Algorithm:
Step
1: Let A = 50 (here we are
assigning the value 50 to A)
Step
2: Let B = 40 (here we are assigning
the value 40 to B)
Step
3: Sum = A + B ( Addition of the value
of A and B and storing result in
Sum)
Step
4: Sum = 90 (Finally displaying result
which is store in Sum i.e 90
Flowchart
for sum of two numbers:
The
Decision making process is used whenever you have to choose one option from
give two option. In other words we can say that you have to give answer in Yes
or No whenever questioned asked to you.
Diamond
shaped symbol is used for decision making while drawing a flowchart.
Consider
the following Algorithm and Flowchart for waking up in the morning. At Step 2
the question is asked and the answer is Yes or No. It is a decision making step
where you have to decide whether to hit snooze or not. This decision taking
step is represented as a diamond in the flowchart
Algorithm:
Step
1: The Alarm rings at a specified time.
Step
2: If you it Snooze, go back to Step1
Step
3:Else wake up
Step
4: Turn off Alarm
Loops:
Repetition
of a sequence of steps until a spefied condition is fulfilled or satisfied is
called loop. In other words we can say that the loop means executing one
statement multiple times as per the specified condition.
Consider
a situation in which a sequence of steps has to be repeated. Look at the
flowchart to understand the loops.
Algorithm:
Step
1: Get the Number 'N'
Step
2: Set variable Count be equal to 1
Step
3: Multiple = N X Count
Step
4: Display Multiple
Step
5: If Count is 10 go to End
Step
6: Add 1 to current value of Count and go to Step 3.
Step
7: End
The
repetition of sequence starts with Count = 1. The value of N (i.e 12) is
multiplied with 1 and output is printed. Since we want to repeat the
multiplication till count become 10 so we will add 1 to the count. In the
second iteration or repeatation the value of Count will become 2 and the value
of N will be multiplied by 2 and output will be printed. A decision box is used
to stop the repetition when the value of count becomes 11.
Question and Answers for Algorithm and Flowchart
Q1.
Fill in the blanks.
a)
The instructions written in a language which computer can understand is called
Computer Program
b)
A set of steps that are followed in order to solve any problem or to complete a
task is called Algorithm
c)
The graphical or pictorial form of an algorithm is called the Flowchart
d)
A Flow line Symbol is used to connect one box of flowchart to another.
e)
A decision box is diamond shape.
Q2.
Match the elements of a flow chart and their purpose of use in the following
situation
Q3.
The following flowchart gives the steps followed while taking attendance in a
class. Three Arrows and a loop are missing. Complete the flowchart as follows:
Draw
three arrows and missing loop at the correct place
Label
the decision arrow with Yes or No
Ans:
