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An algorithm should be (at least)

–complete (i.e. cover all the parts)

–unambiguous (no doubt about what it does)

–finite (it should finish)

3. code the solution

This step consists of translating the algorithm into a computer program using a programming language.

4. test and correct the program

This step requires testing of the completed computer program to ensure that it does, in fact, provide a solution to the problem. Any errors that are found during the tests must be corrected.

Figure below lists the relative amount of effort that is typically expended on each of these four development and design steps in large commercial programming projects.

Four development and design steps in commercial programming projects

Phase ii: documentation

Documentation requires collecting critical documents during the analysis, design, coding, and testing.

There are five documents for every program solution:

  • Program description
  • Algorithm development and changes
  • Well-commented program listing
  • Sample test runs
  • User’s manual

Phase iii: maintenance

This phase is concerned with the ongoing correction of problems, revisions to meet changing needs and the addition of new features. Maintenance is often the major effort, and the longest lasting of the three phases. While development may take days or months, maintenance may continue for years or decades.

Algorithms

An algorithm is defined as a step-by-step sequence of instructions that describes how the data are to be processed to produce the desired outputs. In essence, an algorithm answers the question: “What method will you use to solve the problem?”

You can describe an algorithm by using flowchart symbols. By that way, you obtain a flowchart which is an outline of the basic structure or logic of the program.

Flowchart symbols

To draw flowchart, we employ the symbols shown in the Figure below.

Flowchart symbols

The meaning of each flowchart symbol is given as follows.

Description of flowchart symbols

To illustrate an algorithm, we consider the simple program that computes the pay of a person. The flowchart for this program is given in the Figure below.

Note: Name, Hours and Pay are variables in the program.

A sample flowchart

Algorithms in pseudo-code

You also can use English-like phases to describe an algorithm. In this case, the description is called pseudocode. Pseudocode is an artificial and informal language that helps programmers develop algorithms. Pseudocode has some ways to represent sequence, decision and repetition in algorithms. A carefully prepared pseudocode can be converted easily to a corresponding C++ program.

Example: The following set of instructions forms a detailed algorithm in pseudocode for calculating the payment of person.

Input the three values into the variables Name, Hours, Rate.

Calculate Pay = Hours Rate.

Display Name and Pay.

Loops in algorithms

Many problems require repetition capability, in which the same calculation or sequence of instructions is repeated, over and over, using different sets of data.

Example 1.1. Write a program to do the task: Print a list of the numbers from 4 to 9, next to each number, print the square of the number.

The flowchart for the algorithm that solves this problem is given in Figure below. You will see in this figure the flowchart symbol for decision and the flowline that can connect backward to represent a loop.

Flowcharts of example 1.1

Note:

  1. In the flowchart, the statement

NUM = NUM + 1

means “old value of NUM + 1 becomes new value of NUM ”.

The above algorithm can be described in pseudocode as follows:

NUM = 4

do

SQNUM = NUM*NUM

Print NUM, SQNUM

NUM = NUM + 1

while (NUM<= 9)

You can compare the pseudo-code and the flowchart in Figure above to understand the meaning of the do… while construct used in the pseudo-code.

Flowchart versus pseudocode

Since flowcharts are inconvenient to revise, they have fallen out of favor by programmers. Nowadays, the use of pseudocode has gained increasing acceptance.

Only after an algorithm has been selected and the programmer understands the steps required can the algorithm be written using computer-language statements. The writing of an algorithm using computer-language statements is called coding the algorithm, which is the third step in our program development process.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Programming fundamentals in c++. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10788/1.1
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