L1. Basic Programming Concepts.pdf

Introduction
▪ Computer programs are the collections of instructions that
tell a computer what to do, how to interact with the user,
interact with the computer hardware and process data.
▪ The first programmable computers required the
programmers to write explicit (clear & exact) instructions to
directly manipulate the hardware of the computer.
2

Computer Programs
❖Computer programs, known as software. You tell a computer
what to do through programs.
❖Without programs, a computer is an empty machine.
❖Computers do not understand human languages, so you need to
use computer languages to communicate with them.
3

Programming Languages
⚫ Programs are written using programming
languages.
⚫ Programming language is an agreed upon
format of symbols that allow a programmer to
instruct a computer to perform certain
predefined tasks.
4

Types of programming languages
Some types of programming languages are:
⚫ Machine languages
⚫ Assembly languages
⚫ High-level languages
5

Machine language
⚫ Low-Level language is the only language which can
be understood by the computer.
⚫ Low-level language is also known as Machine
Language.
⚫ Sometimes called machine code or object code
⚫ The machine language contains only two symbols 1
& 0. All the instructions of machine language are
written in the form of binary numbers 1's & 0's.
⚫ A computer can directly understand the machine
language.
6

Assembly language
⚫ Middle-level language in which the instructions
are created using symbols such as letters, digits
and special characters.
⚫ In assembly language, we use predefined words
called mnemonics. Binary code instructions in
low-level language are replaced with mnemonics
and operands in middle-level language.
⚫ But the computer cannot understand mnemonics,
so we use a translator called Assembler to
translate mnemonics into machine language.
7

Assembly language (cont.)
⚫ Assembler is a translator which takes
assembly code as input and produces machine
code as output.
⚫ That means, the computer cannot understand
middle-level language, so it needs to be
translated into a low-level language to make it
understandable by the computer.
⚫ Assembler is used to translate middle-level
language into low-level language.
8

High-level languages
⮚High-level language is a computer language which
can be understood by the users.
⮚ The high-level language is very similar to human
languages and has a set of grammar rules that are
used to make instructions more easily.
⮚Every high-level language has a set of predefined
words known as Keywords and a set of rules
known as Syntax to create instructions.
9

High-level languages (Contd..)
⮚The high-level language is easier to understand
for the users but the computer can not
understand it.
⮚ High-level language needs to be converted into
the low-level language to make it understandable
by the computer.
⮚We use Compiler or interpreter to convert
high-level language to low-level language.
10

Examples of High-Level Languages
Java (An object oriented language). General purpose –
gaining popularity rapidly.
COBOL (Common Business Oriented Language).
Developed for business applications.
FORTRAN (FORmula TRANslation). Developed for
Engineering & Scientific Applications.
BASIC (Beginner All-purpose Symbolic Instructional
Code).
11

Examples of High-Level Languages (cont.)
⚫ C is designed to support only procedure-oriented
programming. Popular language for developing
system applications such as operating system and
compilers.
⚫ C++ is extension of C programming language that
supports object-oriented programming and procedure
oriented approach. General purpose and most popular.
⚫ Visual Basic – Basic-like visual language developed by
Microsoft.
12

Examples of High-Level Languages (cont.)
⚫ PROLOG - is a language for PROgramming in LOGic.
Artificial Intelligence.
⚫ Ada (named after Ada Lovelace)
⚫ Python - is a general purpose programming language
that's used to do things from testing microchips at
Intel, to building video games.
13

The Programming Process
Programming involves five steps to develop a
program.
1. Defining the problem: State the problem clearly.
2. Describe the input and output information.
3. Work the problem by hand (or with a calculator)
for a specific set of data.
4. Develop a solution that is general in nature.
5. Testing the program: Test the solution with a
variety of data sets.
14

Why Programming?
⚫ There are some good reasons for learning programming:
⚫ Computer programming can be used to create
innovative and functional software. Computer
programmers can use their creativity to design software
that will be useful to people, or that will improve the
way that people work.
⚫ Computers can also be programmed to perform specific
tasks using mathematical algorithms and logic.
⚫ It can also be used to create websites, games, and other
digital content.
15

Different Phases of Programming Task
A typical programming task can be divided into
three phases:
1) Pre-programming phase (or Problem Solving Phase)
• Produce an ordered sequence of steps that describe
solution of problem.
• Algorithms as well as Flowcharts are implemented in
problem solving phase of programming.
2) Programming phase(or Implementation Phase)
⚫ implement the program in some programming
language
3) Maintenance Phase
⚫ Maintain/modify to meet changed requirements or
to correct errors.
16

This phase requires four steps:
⮚Analyzing the problem.
⮚Developing the Input-Process-Output
(IPO) Chart.
⮚Writing the algorithm.
⮚Drawing the flowchart.
Pre-Programming Phase
17

Analyzing the problem
❖Understand and analyze the requirements of the
problem.
❖Identify the following:
⚫ Data requirement.
⚫ Processing requirement or procedures that will be needed to solve
the problem.
⚫ The output.
18

All these requirements can be presented in a Problem
Analysis Chart (PAC) as follows:
Data Processing Output
Given in
the
problem or
provided
by the user
List of
processing
required or
procedures
Output/
desired result
19

Problem 1: Calculate the salary of an employee who
works by hourly basis. The formula to be used is:
Salary = Hour works * Pay rate
Hours work,
Pay rate
Salary =
Hours works
* pay rate
Salary
20

Problem 2: Draw a Problem Analysis Chart (PAC) to
find the area of circle where area = pi * radius * radius
radius area = 3.14
x radius x
radius
area
21

Problem 3. Draw a problem analysis chart to convert
the distance in miles to kilometers where 1.609 per
mile.
Distance
in miles
Kilometers
= 1.609 x
miles
Distance in
kilometers
22

Problem 4. Draw a problem analysis chart to find
the area of a triangle.
Problem 5: Draw a problem analysis chart to
evaluate the following expression.
EXP= a²+2ab+b²
23

• Extends and organizes the information in the PAC.
• It shows in more details what items are input, what to
be processed and what will be the result or output.
Developing the Input-Process-Output (IPO)
Chart
24

Problem 1. Develop an IPO chart to convert the distance
in miles to kilometers where 1.609 kilometers per mile.
Input Processing Output
Distance in
miles
-Enter
distance
-Kilometers
= 1.609 x
miles
-Display
kilometers
-Distance in
kilometers
25

26
Constant and Variable
Constant: A constant can be defined as a fixed value,
which is used in algebraic expressions and equations. A
constant does not change over time and has a fixed
value. For example, the size of a shoe or cloth or any
apparel will not change at any point.
Variables: Variables are terms which can change or vary
over time. Its value does not remain constant, unlike
constants. For example, the height and weight of a
person do not always remain constant, and hence they
are variables.

❖In computer programming terms, an algorithm
is a set of well-defined instructions to solve a
particular problem.
❖It takes a set of input(s) and produces the
desired output.
❖Before writing a program, a programmer must
start with an algorithm of the program
following with flowchart and pseudo code.
❖Purpose: Algorithms provide a better
understanding towards programming and helps
in building better problem-solving logic.
Algorithms help the programmer to write code
faster by following steps in Algorithm.
What is algorithm?
27

❖It is not the entire program or code; it is simple logic to a
problem represented as an informal description in the form of a
flowchart or pseudo code.
What is algorithm? (contd..)
28

❖Problem: A problem can be defined as a real-world problem for which you
need to develop a program or set of instructions. An algorithm is a set of
instructions.
❖Algorithm: An algorithm is defined as a step-by-step process that will be
designed for a problem.
❖Input: After designing an algorithm, the algorithm is given the necessary
and desired inputs.
❖Processing unit: The input will be passed to the processing unit, producing
the desired output.
❖Output: The outcome or result of the program is referred to as the output.
What is algorithm? (Contd..)
29

Examples of Algorithm
Problem 1. Write an algorithm to “Make
Tea”
Algorithm
Step1. Start.
Step2. Take water in pan
Step3. Boil the water
Step4. Add sugar and Tea leaves
Step5. Add milk
Step6. Boil it
Step7. Pour it into cup
Step8. Stop
30

There may be more than one way to solve a problem,
so there may be more than one algorithm for a
problem.
Before writing an algorithm for a problem, one should
find out what is/are the inputs to the algorithm and
what is/are expected output after running the
algorithm.
31

While writing algorithms we will use following
symbols for different operations:
+ for Addition
- for Subtraction
* for Multiplication
/ for Division and
for assignment. For example
A X*3 means A will have a value of X*3.
32

⮚ Input: An algorithm requires some input values. An algorithm can be given a value
other than 0 as input.
⮚ Output: At the end of an algorithm, you will have one or more outcomes.
⮚ Unambiguity: A perfect algorithm is defined as unambiguous, which means that its
instructions should be clear and straightforward.
⮚ Finiteness: An algorithm must be finite. Finiteness in this context means that the
algorithm should have a limited number of instructions, i.e., the instructions should
be countable.
⮚ Effectiveness: Because each instruction in an algorithm affects the overall process,
it should be acceptable.
⮚ Language independence: An algorithm must be language-independent, which
means that its instructions can be implemented in any language and produce the same
results.
The essential properties of
Algorithm are:
33

Steps for Developing an Algorithm
✔Define the problem: State the problem you are trying to solve
in clear and concise terms.
✔List the inputs (information needed to solve the problem) and
the outputs (what the algorithm will produce as a result)
✔Describe the steps needed to convert or manipulate the inputs
to produce the outputs. keep refining the steps until they are
effectively computable operations.
✔Test the algorithm: choose data sets and verify that your
algorithm works!
34

Examples of Algorithm
Problem 2: Find the area of a Circle of radius r.
Algorithm:
Step1: Start
Step2: Readinput the Radius r of the Circle
Step3: Area PI*r*r // calculation of area
Step4: Print Area
Step5: Stop
35

Problem 3: Write an algorithm and draw a flow chart
to read two numbers and find their sum.
Algorithm:
Step 1 : Start
Step 2 : Input first number A
Step 3 : Input second number B
Step 4 : Total = A+B
Step 5 : Print Total
Step 6 : Stop
36

Practice Algorithm
✔Algorithm 1: Find the largest number between
two numbers
✔Algorithm 2: Find the odd and even number
from a given input value.
37

Flowchart
◆ A flowchart is simply a graphical representation of steps. It
shows steps in sequential order and is widely used in
presenting the flow of algorithms, workflow or processes.
◆ Typically, a flowchart shows the steps as boxes of various
kinds, and their order by connecting them with arrows.
◆ Flowcharts are very helpful in writing programs and explaining
them to others.
◆ Flowcharts 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 programming language.
38

When to use a flowchart?
★ It is most importantly used when the programmers
make projects. As a flowchart is a basic step to make
the design of projects.
★ When the flowcharts of a process are drawn, the
programmer understands the non-useful parts of the
process. So flowcharts are used to separate useful logic
from the unwanted parts.
★ Since the rules and procedure of drawing a flowchart
are universal, flowchart serves as a communication
channel to the people who are working on the same
project for better understanding.
39

BASIC FLOWCHART SYMBOLS ARE
GIVEN IN THE NEXT SLIDE
40

Symbol Name Use in flowcharts
Start/Stop
(Oval)
Denotes the beginning or end of
the program
Flow line Show the direction of data flow
or logical solution
Process
(Rectangle)
Indicates a process to be carried
out such as addition, subtraction,
multiplication and division.
Input/Output
(Parallelogram)
Indicates input to the program or
output from the program
41

Symbol Name Use in flowcharts
Question,
Decision
(Diamond)
Used for making a decision. The
program should continue along one of
two routes; either true or false based
on certain conditions.
Connector
(Circle)
Connection of flowchart on the same
page.
Connector Connection of flowchart from one
page to another.
42

1. Use conventional flowchart symbols. Each symbol should
have one exit point except the decision symbol. As far as
possible each symbol should also have one entry point and
in the case of decision symbol, it is a must.
2. The flow of control in the problem can be shown with the
help of arrows. But, the flow lines should not cross each
other.
3. The processing logic within the flowchart should flow from
top to bottom and from left to right.
4. The instructions written within the various flowchart
symbols should be independent of programming languages.
General Rules for flowcharting
43

5. The flow lines coming out of the decision symbol
should be properly labelled.
6. If the flowchart becomes large and complex (on same
page) then make use of ordinary connector symbols to
avoid crossing of flow lines.
7. Every flow chart must have the start and End points.
44
General Rules for flowcharting
(contd..)

➔ Communication: Flow charts are better way of
communicating the logic of a system to all
concerned.
➔ Effective analysis: With the help of flowchart,
problem can be analyzed 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.
Advantages of Using Flowcharts
45

➔ 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.
46
Advantages of Using Flowcharts (contd)

Flow chart
47
Example: Draw a flowchart to sum two numbers.

Algorithm
Step 1 : Start
Step 2 : Read value for a side A
Step 3 : [Compute] Area A * A
Step 4 : Print Area
Step 5 : Stop
Problem: Algorithm and a flow chart to calculate
area of square.
48

Algorithm
Step1 : Start
Step 2 : Enter Three Numbers A, B and C
Step 3 : Compute Average = (A+B+C)/3
Step 4 : Print Average
Step 5 : Stop
Problem: Algorithm and flowchart to find the average
of three numbers.
50

52
Relationship between Celsius and Fahrenheit

Algorithm:
Step 1: Start
Step 2: Read Temperature in Fahrenheit F
Step 3: C (F - 32)*(5/9)
Step 4: Print Temperature in Celsius C
Step5: End
54
Problem 3: Convert temperature Fahrenheit to
Celsius

Algorithm:
Step 1: Start
Step 2: Read Temperature in Celsius C
Step 3: F ( 9 * C / 5 ) + 32
Step 4: Print Temperature in Fahrenheit F
Step5: End
56
Problem 3: Convert temperature Celsius to
Fahrenheit

57
1. Write an Algorithm and Draw a Flowchart to find
the third angle of a triangle if two angles are given.
2. Write an Algorithm and Draw a Flowchart to
enter Principal, Time, Rate and calculate the
simple interest
3. Write an Algorithm and Draw a Flowchart to
calculate a bike’s mileage from the given total
distance (integer value) traveled (in km) and spent
fuel (in liters, float number up to 2 decimal point).

59
Write an algorithm to find out if a given number is Even
or Odd.
Step 1: Start
Step 2: Declare variable a
Step 3: Input a
Step 4: if a%2==0
go to step 5
else go to step 6
Step 5: Print Even
Step 6: Print Odd
Step 7: Stop

Algorithm
Step 1: Start
Step 2: Declare variables A, B
Step 3: Enter two numbers A and B
Step 4: If A>B
Go to Step 6
else go to Step 5
Step 5: If B>A
Go to step 7
else go to step 8
Step 6: Print A is greater
Step 7: Print B is greater
Step 8: Print A and B are Equal
Step 9: Stop
Problem: Write the algorithm and draw the
flowchart to compare two numbers?
60

62
Step 1: Start
Step 2: Declare variables M1, M2, M3, M4, GRADE
Step 3: Input M1,M2,M3,M4
Step 4: GRADE ← (M1+M2+M3+M4)/4
Step 5: if (GRADE >=60)
then go to step 7
else go to step 6
Step 6: Print “FAIL”
Step 7: Print “PASS”
Step 8: Stop
Write an algorithm to determine a student’s final grade
and indicate whether it is pass or fail. The final grade is
calculated as the average of four marks.

Flow Chart
START
Input
M1,M2,M3,M4
GRADE←(M1+M2+M3+M4)/4
IS
GRADE>=60
STOP
YES
NO
63
Print Fail Print Pass

Algorithm
Step 1: Start
Step 2: Declare sum, I, N
Step 2: Read number N
Step 3: Set sum = 0 and i = 1
Step 4: Repeat steps 5 and 6 until i<=N
Step 5: update sum as sum sum + i
Step 6: increment i
Step 7: Print sum
Step 8: Stop
Algorithm and a flow chart to calculate the
sum of N natural numbers.
64

Practice session:
Draw the flowchart to print sum of all even numbers
between 1 to n.
66

L1. Basic Programming Concepts.pdf

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