CHAPTER 1

ec201/unit 1/introductory to programming 1
UNIT 1
INTRODUCTORY TO
PROGRAMMING

OBJECTIVES
General Objective :To Understand the Programming Concept
and terminology, stage involved in Problem Solving and
Programming development.
Specific Objectives : At the end of the unit you will be able to:
1. Define programming concept and
terminology
2. Explains on the stages involved in
problem
solving
3. Use the design tools to solve a given
problem
4. Define errors in ptogramming
2
ec201/unit 1/introductory concepts

Introduction To Programming
important characteristics of well-written computer
programs.
 Integrity : This refer to the accuracy of the
calculations since it will be meaningless if
calculations are not carried out correctly.
 Clarity : This refer to the overall readability of the
program, with particular emphasis on its
underlying logic. If a program is clearly written, it
should be possible for programmer to follow the
program logic with ease.
3

Cont…
 Simplicity : The clarity and accuracy of a
program are usually enhanced by keeping
things as simple as possible, consistent with
the overall program objectives.
 Efficiency : This is concerned with execution
speed and efficient memory utilization.
4

Cont…
 Modularity : Many programs can be broken
down into a series of identifiable subtask that
enhances accuracy and clarity of a program
and facilitates future program alterations.
 Generality : Usually we will want a program to
be as general as possible, within reasonable
limits. A considerable amount of generality can
be obtained with very little additional
programming effort.
5

Definition of Programming Terms
6
 Programme
A set of instructions that tells the computer
what to do.
 Programmer
A person who writes a program so that data
may be processed by a computer.

Cont...
7
 Programming language
A programming language is an artificial
language designed to express computations
that can be performed by a machine,
particularly a computer. Programming
languages can be used to create programs
that control the behavior of a machine, to
express algorithms precisely, or as a mode of
human communication.

Types of Popular Programming Languages
8
 BASIC
BASIC (Beginner's All-purpose Symbolic
Instruction Code) is a family of
high-level programming languages to provide
computer access to non-science students.
Example: HELLO WORLD
main( )
{
printf("hello, world");
}

Cont…
9
 QBasic
QBasic (QuickBASIC) is an IDE (
integrated development environment) and
interpreter for a variant of the
BASIC programming language.
PRINT "Hello, World!"

Cont…
10
 Visual Basic
Visual Basic (VB) is the third-generation
event-driven programming language and
integrated development environment (IDE) from
Microsoft for its COM programming model.
Private Sub Form_Load()
' Execute a simple message box that will say "Hello,
World!"
MsgBox "Hello, World!"
End Sub

Cont…
11
 C
C (pronounced /si/ s e e ) is a designed for
implementing system software and used for
developing portable application software.
#include <stdio.h>
int main(void)
{
printf("hello, worldn");
return 0;
}

Cont…
12
 C++
C++ (pronounced /si plas plas/ s e e p lus p lus )
is a statically typed, free-form, multi-paradigm,
compiled, general-purpose
programming language.
Examp#ilnec:l uHdEe L<iLosOtr eWamO>R LD
int main()
{
std::cout << "Hello, world!n";
}

Cont…
13
 Pascal
Pascal is an influential imperative and
procedural programming language
program
HelloWorld(output);
begin
Writeln('Hello world!')
end.

Types of Programming
14
Structured programming
A technique for organizing and coding
computer programs in which a hierarchy of
modules is used, each having a single entry
and a single exit point, and in which control is
passed downward through the structure
without unconditional branches to higher
levels of the structure. Three types of control
flow are used: sequential, test, and iteration.

Cont…
15
Modular programming
Modular programming is a software design
technique that increases the extent to which
software is composed of separate,
interchangeable components, called modules.

Cont…
16
Object-Oriented programming
Object-oriented programming (OOP) is a
programming paradigm that uses "objects"
– data structures consisting of data fields
and methods together with their interactions
– to design applications and computer
programs.

Stage involved in Problem Solving
17
It consists of several steps which are
known as software life cycle, these are:
 Defining and Analyzing Problems
 Planning of Variables
 Design Tools
 Program Writing
 Program Testing and Debugging
 Program Documentation

Defining and Analyzing Problems
18
 to identify and understand the problems to
resolve. The problems must be clearly define,
explicit and the requirements in resolving it.
Analyzing the problems will determine the input,
process and output, as follows:
 Input – d a ta to be p ro c e s s e d
A set of information called data will be entered into
the computer from keyboard, floppy disk, hard disk
etc. and stored in a portion of the computer
memory.
Explaination: cin (console input) for input – normally
assigned to the keyboard.

Cont…
19
Process
Sequence of interdependent and linked
procedures which, at every stage, consume
one or more resources to convert inputs into
outputs. These outputs then serve as inputs
for the next stage until a known goal or end
result is reached.

Cont…
20
Output – the d e s ire d re s ult
The processed data which produced certain
result is known as the output. The output data
will be presented in a sheet of paper through
the printer or display on a monitor.
Explanation: cout (console output) for output
– normally assigned to the screen.

Planning of Variables
21
 Variables are simply references to
memory locations. A well plan use of
variables will produce an efficient
execution of program in terms of speed
and memory utilization.

Design Tools
22
 Programmer will design the whole program,
starting from getting the data, process the data
and produce the desire output.
 Flowchart represents algorithm in graphic form
comprising of geometrical symbols which is
interrelated by line of flow.
Flowchart
Flowcharts are a visual outlining tool or
geometrical symbols. They can be used to
represent an algorithm.

Cont…
23
SYMBOL NAME MEANING
Flowline Used to connect symbols and
indicate the flow of logic
Terminal
Used to represent the
beginning (start) or the end
(End) of a task
Input/outp
ut
Used for input and output
operations, such as reading
and printing. The data to be
read or printed are describe
inside

Cont…
24
SYMBOL NAME MEANING
Processing Used for arithmetic and data-manipulation
operations. The
instruction are listed inside
the symbol
Decision Used for any logic or
comparison operations. The
path chosen depends on
whether the answer to a
question is “yes” or “no”

Cont…
25
SYMBOL NAME MEANING
Connector Used to join different flowline
Offpage
connector
Used to indicate that the flow
chart continues to a second
page
Predefined
Process
Used to represent a group of
statements that perform one
processing task

Cont…
26
Pseudocode
Pseudocode is another way to develop the logic
of a
program. It is merely writing down the steps to
solve
the problem in the correct and logical order. The
process is similar to doing an outline before you
write
a report.

Cont…
27
Example: A program is required to read three
numbers, add them together and print
their
total.
Solution:
1. Enter the first number
2. Enter the second number INPUT
3. Calculate processing. ‘ADD (+) command –
PROCESS
4. Get the total of numbers result – OUTPUT

Cont…
28
IPO chart (Input-Process-Output chart)
IPO is an acronym for Input, Processing and Output.
Each
letter represents a column in this three column form:
 First column lists the variables for the Inputs.
 Second column shows any processing items
(variables created within the code) as well as
the pseudocode or flowchart used to solve the
problem.
 Third column list the variables that are to be
output.

Cont…
29
Example: A program is required to read three
numbers, add them together and
print their total.
Solution:
INPUT PROCESSING OUTPUT
number_1
number_2
number_3
number 1 + number 2 +
number 3 =
Total of
numbers

Program Writing
30
In the design of program it should be written as
simple as possible. The main objective is to give
a
clear, readable programs through an orderly and
disciplined approach to programming.

Cont…
31
Comments
Comments are used to insert remarks into the
source
code help to explain about what the program
does. In
C, comments can be place anywhere in the
programs.
It can be used to include the details of the
project and
the programmer who wrote or modified the code.

Cont…
32
There are two types of comment used. They are:
 Multi-line Comment
This type of comment is begins with a /* (slash
followed by an asterisk) symbol and ended with
a */
(asterisk followed by an slash) symbol.
This ty p e o f c o m m e nt is g o o d to be us e d whe n
c o m m e nts writte n a re lo ng e r tha n 1 line .

Cont…
33
Example:
/* This is a program that computes the sum of two
integer
numbers * /

Cont…
34
 Single line Comment
This type of comment is used with the // (double
slash) symbol and it stops at the end of that
particular
line.
This ty p e o f c o m m e nt c a n be us e d whe n the
re m a rk is
o nly 1 line in le ng th.

Cont…
35
Example:
// This is a preprocessor

Cont…
36
 Header Files
Header files contain information that is required
to
run a program. It is a pre written and tested
function
that comes together with the compiler and is
available
for the use of the programmers.
#include <iostream.h>
Example:

Cont…
37
 Functions
A function is a block of statements that is part of
a
large program.
 Function main( )
A C program must have at least the function
main( ).
Every C function, including main( ), must have a
body
enclosed in braces { }.

Cont…
38
 Function block { }
The function body, also called blo c k can be of
any
size. The function always ends with the re turn
command.
{ - begin block
} - end block

Cont…
39
Example:
main ( )
{
}

Cont…
40
 Format Code ( Backslash Character Constant)
The backslash character constant is also known
as the
‘Escape Sequence’.

Cont…
41
CODE MEANING
b Backspace
f Form Feed (Page
Feed)
n Newline
r Carriage Return
t Horizontal Tab
v Vertical Tab
’ Single Quote (‘)
” Double Quote (“)
Backslash ()
a Alert (beep)
? Question Mark (?)

Cont…
42
Example:
/* This is a program that computes the sum of two integer
numbers */
#include <iostream.h> // This is a
preprocessor
main( ) // include directive
{
int x, y, sum;
cout << “nEnter first number:”; // This is a prompt
cin >> x; // Input from console
cout<< “nEnter second number:”;
cin>>y;
sum = x + y; // Adding x and y
cout << “nSum =” <<sum; // Output to console
return 0; // Returning a value to the
environment
}
comment
Preprocessor
directive
Function name
Begin block
Function Body
End Block

Program Testing and Debugging
43
Once the program has been written it must be
compiled and executed. This is accomplished by
an
editor and compiler.
An editor lets us type a program, makes
changes and
save it to a file.
The compiler then translates the program into a
form
that the computer can read.
Once the program has been compiled and
executed

Cont…
44
Syntactic and execution errors usually result in
the
generation of error when compiling or executing
a
program.
Syntax Error
The most common error a programmer makes.
Usually
a miss spelled word. A program will not compile
until
all syntax errors are corrected.

Cont…
45
Run-Time Error
Run-time errors are errors that occur while your
program runs. These typically occur when your
program attempts an operation that is
impossible to
carry out.
Logical Error
These errors solely depend on the logical
thinking of
the programmer and are easy to detect if we
follow
the line of execution and determine why the
program

Program Documentation
46
Program must be documented for future
references
and maintenance process. A well documented
program will make it easier for the original
programmer or other programmer to follow the
program logic and design.

Cont…
47
Program document should consist of:
An accurate specification of
requirement.
Detail input, output, constraint and
formula for the above problems.
Algorithm in the form of flowchart or
pseudocode.
Program source complete with
comment.
Sample program which had been run
and executed and the tested data.
 Guideline on how to use the program.

CHAPTER 1

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