Introduction to Programming & 2 Student registration & introduction to the module Introduction to programming methodology Programming language levels Factors to consider while selecting

Introduction to Programming

1 The Catholic University of Eastern Africa

P.o Box 62157-00200, Nairobi Kenya

© Edward Kioko 2013

Machakos University College

(A constituent College of Kenyatta University)

P.O Box 136-90100, Machakos Kenya Telephone: 044-21604 Email: [email protected] Website:

http://www.machakosuniversity.ac.ke

SCO102: introduction to programming

Prepared by:

Edward M Kioko

Email:[email protected]

Tel:+254 (0) 725 695 782

August, 2014

Purpose of the module

In this 3 month instructor-led course, student shall learn the

fundamental skills for programming languages. Learners will use a

high level language (C programming language) to solve scientific

problem. The module provides a basic an entry point for students in

the field of software engineering.

Learning Outcomes

By the end of the module, students will be able to:

Understand the basic principles in programming

Understand problem solving strategies

Understand the process of creation of a computer

program and the different approach

Use high level language to code, write, compile, link

and execute a program with emphasis on scientific

applications

tel:+254





Course outline

Programme : BSc Computer science

Module Name : introduction to programming

Module Code : SCO 102

Credit Hours : 2hours per week; Lab work 3 hours per

week Semester

Semester : August-Dec 2014/2015

Course Leader : Edward Kioko

Meeting hours : Friday 8:00-1:00

Venue : Electrical Lab

E-mail : [email protected]

Website : http://www.edwardchris.net

Program : Regular

Module Schedule (August –December 2014/2015)

Week

Topic/Content Comment

1 & 2 Student registration & introduction to the module

Introduction to programming methodology

Programming language levels

Factors to consider while selecting a

programming language

Translators

Overview of C language

Development environment and cycle

Syntax of a C program

3 Program design and logic

Algorithm

Flowcharts & Pseudo code

4 & 5

Basic Elements of programming

Identifiers and keywords

Commenting in

data types

Operators

Constants and variables

6 & 7

Control structures

Decision control structure

loop

Continuous Assessment Test

8 & 9 Modular programming in C( functions)

mailto:[email protected]

http://www.edwardchris.net/





10 & 11

Arrays in C

Lab Practical

END OF SEMESTER EXAMINATIONS

Teaching Methodologies:

Lectures, demonstrations, group/class discussions and practical

exercises

Instructional Materials/Equipment:

Computers, projectors, whiteboards and writing materials.

Course Assessment:

I CAT: 10%

Assignments 10%

Lab 20%

Exam: 60% .

100%

Recommended References:

1. Kerinignan, B. W., & Ritchie, D. M. (2010). The C

programming Language (second Edition ed.). New jersey:

Prentice Hall P T R.

2. King, K. C Programming: A Modern Approach.





Contents Chapter One: Introduction to programming ...................................... 6

1.1 Chapter objectives ............................................................... 6

1.2 Introduction to programming .............................................. 6

1.3 Programming levels............................................................. 6

1.4 Factors to consider while selecting a programming

language ....................................................................................... 10

1.5 Translators ......................................................................... 11

1.6 The development environment and the development cycle

13

1.7 Overview of C language .................................................... 13

1.8 C program structure and syntax ........................................ 13

1.9 Chapter summary .............................................................. 15

1.10 Chapter exercise ............................................................ 15

1.11 Further reading suggestion ............................................ 15

Chapter Two: Program Design Process and Logic .......................... 16

2.1 Chapter objectives ............................................................. 16

2.2 Introduction ....................................................................... 16

2.3 Program development Lifecycle (PDLC) ......................... 16

2.4 Programming design and logic tools ................................. 17

2.5 Algorithms ......................................................................... 17

2.6 Flow charts ........................................................................ 18

2.7 Pseudocode........................................................................ 20

2.8 Control Structures/Logical Structures ............................... 21

2.9 Chapter summary .............................................................. 27

2.10 Chapter exercise ............................................................ 27


3.2 Introduction ....................................................................... 28

3.3 Key words ......................................................................... 28

3.4 Comments in C.................................................................. 28

Chapter three: Fundamentals of C programming ............................ 28

3.5 Data types in C .................................................................. 29

3.6 Variables ........................................................................... 30

3.7.1 Numeric variables ........................................................ 31

3.7.2 Character variables ..................................................... 31

3.7.3 Assignment ................................................................... 31

3.7 Constants in c programming ............................................. 32

3.8 Arithmetic operators ......................................................... 32

3.9 Escape sequence ................................................................ 32

3.10 Statements ..................................................................... 32

3.11 Casting Data Types ....................................................... 32

3.12 Input and output ............................................................. 33





3.13 Formatted input–scanf ................................................... 33

3.14 Character I/O — getchar& putchar ............................... 35

Chapter Four: Control structures in C .............................................. 36

5.1 Introduction ....................................................................... 36


5.3 Boolean expressions and relational operators ................... 36

5.4 Compound Boolean expressions using logical operators .. 36

5.5 Control structures in C ...................................................... 37

5.6 Decision control structures ................................................ 37

4.5.1 Switch statement in C .................................................... 41

5.7 Repetitive control structures in C ...................................... 42

5.8 Chapter summary .............................................................. 46

5.9 Chapter exercise ................................................................ 47

5.10 Further reading suggestions ........................................... 47

Chapter Five: Functions in C ........................................................... 48

5.1 Introduction ....................................................................... 48


5.3 Benefits associated with Functions ................................... 48

5.4 Defining a function in C.................................................... 48

5.5 Function declaration .......................................................... 49

5.6 Function calls .................................................................... 50

5.7 Parameters and arguments ................................................ 51

5.8 Recursive functions in C ................................................... 53

5.8.1 Number Factorial ........................................................... 54

5.8.2 Fibonacci Series ............................................................ 54

5.9 Variable scope ................................................................... 55

5.9.1 Local Variables .............................................................. 55

5.9.2 Global Variables ............................................................ 56

5.9.3 Formal Parameters ......................................................... 57

5.10 Chapter summary .......................................................... 58

5.11 Chapter exercises ........................................................... 58

5.12 Further reading suggestions ........................................... 58


6


P.o Box 136-90100 Machakos|Tel:044-21604|Fax:044-20253

Website: www.machakosuniversity.ac.ke

Chapter One: Introduction to programming

1.1 Chapter objectives

By the end of this, learners should be able to:

Understand programming levels

Learn fundamental concepts underlying programming

languages

Understand the Program Development Life Cycle (PDLC)

Understand the factors to consider while selecting a

programming language

Indentify the different parts of a C program

Able to write, debug and execute a simple C program

1.2 Introduction to programming

Users communicate with the computer in a language understood by

it. It needs to be instructed to perform all the tasks. The instructions

are provided in the form of computer programs, which are

developed by a programmer using a programming language. The

language, which the user employs to interact with the computer is

known as computer programming language. The process of using

such languages to instruct the computer is known

as programming or coding.

We can therefore define a programming language as computer

language used by programmers to develop applications, scripts, or

other set of instructions for a computer to execute.

It is a series of instructions that instruct the computer on how to

perform tasks

1.3 Programming levels

The figure below is intended to illustrate several key points about

programming languages. First, programming languages are built

upon and relate directly to the underlying computer (hardware). In

fact, they are designed to control the operation of the hardware.

Second, these programming languages can be divided into TWO

major groups; low and high level programming languages

Low-level Languages are machine-dependent i.e. must run

on specific machines. They require extensive knowledge of

computer hardware and its configuration. They are further

divided in to Machine language and Assembly language

High-Level Languages are machine-independent hence can

ran on different types of machines

http://www.computerhope.com/jargon/s/script.htm


7




Figure 1: Levels of Programming Languages

Machine Language

It’s the only language that is directly understood by the computer

therefore it does not need any translation. Its written as strings of 1′s

(one) and 0’s (zero. Program instruction may look like this:

1011000111101. It is considered to be first generation language.

Advantage of Machine Language

The only advantage is that program of machine language run very

fast because no translation program is required for the CPU.

Disadvantages of Machine Language

It is very difficult to program in machine language. The

programmer has to know details of hardware to write

program.

The programmer has to remember a lot of codes to write a

program which might easily result in program errors.

It is difficult to debug the program.

Assembly Language

Instead of using a string of binary bits in a machine language,

assembly language use English-like words as commands that can be

easily interpreted by programmers. These commands are referred to

as mnemonics. Examples of mnemonics in assembly language

include ADD, SUB, MUL, DIV.

Programming Language

Low Level High level

Machine Language Assembly Language

Procedural Object oriented


8




Assembly language source must be translated into machine code by

a separate program known as assembler. The machine code can run

on its own at any time therefore the assembler and the source code

are no longer needed.

If you make any changes to the source code, the assembler shall be

needed to recompile the program again and generate a new object

program.

Advantages of Assembly Language

Mnemonics are easier to understand hence saving the

programmer lot of time and effort.

It is easier to correct errors and modify program instructions.

Assembly Language has the same efficiency of execution as

the machine level language. Because this is one-to-one

translator between assembly language program and its

corresponding machine language program.

Disadvantages of Assembly Language:

Its machine dependent hence a program written for one

computer might not run in other computers with different

hardware configuration i.e. there is no program portability.

It is necessary to remember the registers of CPU and

mnemonic instructions by the programmer.

Several mnemonic instructions are needed to write in

assembly language than a single line in high-level language.

Thus, assembly language programs are longer than the high

language programs.

1.3.1.1 Advantages of Low-level Languages

Low-level languages have the advantage that they can be written to

take advantage of any peculiarities in the architecture of the central

CPU. Thus, a program written in a low-level language can be

extremely efficient, making optimum use of both computer memory

and processing time.

1.3.1.2 Disadvantages of Low-level Languages

To write a low-level program takes a substantial amount of time, as

well as a clear understanding of the inner workings of the processor

itself. Therefore, low-level programming is typically used only for

very small programs, or for segments of code that are highly critical

and must run as efficiently as possible.

1.3.1.1 High-Level Languages

High-level programming languages allow the specification of a

problem solution in terms closer to those used by human beings.

These languages were designed to make programming far easier,


9




less error-prone and to remove the programmer from having to know

the details of the internal structure of a particular computer. These

high-level languages were much closer to human language.

Examples include Java, Python, Prolog e.t.c.

They are very convenient but very far removed from the computer

they are running on. They are independent hence can run on

different types of machines

Programming paradigms

Procedural programming

Programming instructions to tell the computer what to accomplish

and how to accomplish it. Some common procedural programming

languages include BASIC, COBOL, C among others e.t.c

Object Oriented Approach

Structured programming doesn’t explain how to keep data and

programs together. However with OOP approach, data and programs

(methods) are packaged into a single unit called an object. OOP are

event driven. Example of OOP languages include C ++, java and

java applets

Advantages of High-level Languages

High-level languages permit faster development of large programs.

The final program as executed by the computer is not as efficient,

but the savings in programmer time generally far outweigh the

inefficiencies of the finished product. This is because the cost of

writing a program is nearly constant for each line of code, regardless

of the language. Thus, a high-level language where each line of code

translates to 10 machine instructions costs only one tenth as much in

program development as a low-level language where each line of

code represents only a single machine instruction.

1.4 Web page program development tools

They are tools used to create web pages. Example of these tools

includes:

HTML (Hypertext MarkUp Language) - it’s not actually a

programming language but contains special codes used to

create and format web pages. It usually uses tags that should

be kept as an ASCII file

Dynamic HTML(DHTML)-allows users to add more

graphics and interactivity on the web page e.g. perform

animations.

Extensible MarkUp language (XML) allows web page

developers to create tags that describe data pass to client so

that the client can process the data rather than the server.


10




XHTML( eXtensible HTML) includes features of HTML

and XML

WML (Wireless Markup Language) allows web page

developers to design pages specifically for micro browsers. It

uses the Wireless Application Protocol (WAP)

Web page authoring which include Dreamweaver,

FrontPage, Joomla flash e.t.c.

1.5 Factors to consider while selecting a programming language

The features of one programming language may differ from the

other. One can be easy and simple, while others can be difficult and

complex. A program written for a specific task may have few lines

in one language, while many lines in the other. We judge the success

and strength of a programming language with respect to standard

features.

There a number of factors while selecting a programming just to

mention a few

Ease of Use

It’s the most important factor in choosing a language. The language

should be easy in writing codes for the programs and executing

them. The ease and clarity of a language depends upon its syntax. It

should be capable enough to provide clear, simple and unified set of

concepts. The vocabulary of the language should resemble English

(or some other natural language). Symbols, abbreviations and

jargons should be avoided unless they are already known to most

people. Any concept that cannot be easily explained to amateurs

should not be included in the language.

Good Programming Language Features

Its definition should be independent of any particular hardware or

operating system. It should support software engineering

technology, discourage or prohibit poor practices, and promote or

support maintenance activities. It should support the required level

of system reliability and safety. If the language does not support the

basic requirements, then it is advisable to learn a new language and

then start the application development.

Nature of Application

Each language provides certain distinctive features, which separates

it from other languages. For example, Java should be used to write

an application that runs over the Internet, whereas to develop a

system application, C and C++ are used.


11




Language Acquaintance

In cases where a number of languages may suit the application to be

developed, the most familiar language to the programmers should be

chosen.

Ease of Learning

Sometimes, it may necessity the programmer has to learn a new

language in order develop an application. In such a case, the first

step is to find out which language, along with its alternatives, would

be suitable for the proposed application. Then, the programmer has

to decide which language is easier to learn and use.

Control over Resources

Apart from the ease of use, the control factor should also be

considered while selecting a language. Easy to learn and use feature

of the language does not mean that the application created with it

will be the most powerful. Certain applications require more control

over the hardware and hence the control factor should not be

ignored. If the application developed by an easy language is not

efficient enough, then it is better to slug it out with a more complex

language. For example, Visual Basic provides an easier way to

develop an application, but it does not have the same control over

the resources as other languages such as Visual C++ or Delphi.

1.5.1 Speed Requirement

Some applications e.g. railway or air reservation need to be quick as

compared to batch processing applications such as payroll and

inventory control. In such cases, the execution efficiency is

important and the programmer should use assembly language

instead of high-level languages. The main reason behind this is that

assembly language usually has a shorter production time as

compared to high-level languages.

1.6 Translators

It’s a program that converts source statement into machine language.

The source statements are just like English words. The computer

interprets the instructions as 1's and 0's. A program can be written in

assembly language as well as in high-level language. This written

program is called the source program. The source program is to be

converted to the machine language, which is called an object

program

Translators can be classified as depicted below follows


12




Translators are as follows:

a) Assembler

b) Compiler

c) Interpreter

1.6.1 Assembler

They are programs that convert assembly code to equivalent

machine code. It will translate the symbolic codes of programs of an

assembly language into machine language instructions. The

symbolic language is translated to the machine code in the ratio of

one is to one symbolic instructions to one machine code instructions.

1.6.2 Compiler

It is a program which translates a high level language program into

a machine language program. A compiler is more intelligent than an

assembler. It checks all kinds of limits, ranges, errors etc. But its

program run time is more and occupies a larger part of the memory.

It s relatively slow in speed since it goes through the entire program

and then translates the entire program into machine codes.

If a compiler runs on a computer and produces the machine codes

for the same computer then it is known as a self compiler or resident

compiler. On the other hand, if a compiler runs on a computer and

produces the machine codes for other computer then it is known as a

cross compiler.

Compilers will show errors and warnings for the statements

violating the syntax rules of the language. They also have the ability

of linking subroutines of the program.

1.6.3 Interpreter

It translates high level languages into machine code. It translates

only one statement of the program at a time. It reads only one

statement of program, translates it and executes it. Then it reads the

next statement of the program again translates it and executes it. In

this way it proceeds further till all the statements are translated and

executed.

On the other hand, a compiler goes through the entire program and

then translates the entire program into machine codes. A compiler is

5 to 25 times faster than an interpreter.


13




By the compiler, the machine codes are saved permanently for

future reference. On the other hand, the machine codes produced by

interpreter are not saved. An interpreter is a small program as

compared to compiler. It occupies less memory space, so it can be

used in a smaller system which has limited memory space.

1.7 The development environment and the development cycle

Programs goes through 3 main phases during development: editing

(writing the program), compiling (i.e., translating the program to

executable code and detecting syntax errors) and running the

program and checking for logical errors (called debugging).

1. Editing

This involves typing in the program with a text editor and making

corrections if necessary. The program is stored as a text file on the

disk

2. Compile

The translator converts the source into machine language code

(object code), which it stores on the disk .A linker then links the

object code with standard library routines that the program may use

and creates an executable image, which is also saved on disk,

usually as a file with the file name without any extension (e.g.

hello).

3. Execute

The executable is loaded from the disk to memory and CPU

executes the program one instruction at a time.

1.8 Overview of C language

It was developed in 1972 by Dennis Ritchie at the Bell telephone

laboratories for use with Unix operating system. It was designed for

system programming because of its low level memory management

and its construct are close to the machine instructions.

1.9 C program structure and syntax

Every C program consists of a header and a main body and has the

following structure.

// Comment statements, which are ignored by computer

#include <header file name >

Void main()

{

declaration of variables ;

statements ;

return 0;

}

We will consider each line of the above program for convenience

the program is reproduced on the next page with line numbers to


14




allow us to comment on details of the program. However, you must

not put line numbers in an actual program.

Line 1: At the top of the program are comments and instructions,

which will not be executed. Lines beginning with // indicate

that the rest of the line is a comment. Comments are inserted

by programmers to help people read and understand the

program. Here the comment states the purpose of the program.

Comments are not executed by the computer. They can in

general be placed anywhere in a program.

Line 2: Lines beginning with # are instructions to the compiler’s

pre-processor. They include instruction says ―what follows is a

file name, find that file and insert its contents right here‖.

It is used to include the contents of a file of definitions that

may be used in the program.

Line 3 The word main is very important, and must appear once (and

only once) in every C program. This is the point where

execution is begun when the program is run. It does not have

to be the first statement in the program but it must exist as the

entry point. The use of the term main is actually a function

definition. Functions must return a value and the term void is

used to denote that the main program does not return a value.

Following the ―main‖ program name is a pair of parentheses,

which are an indication to the compiler that this is a function.

The two braces are used to define the limits of the program

itself: in this case, the main function. The actual program

statements go between the two braces.

Line 4 The opening (left) brace marks the beginning of the main

body of the program. The main body consists of instructions,

which can be declarations defining the data or statements on

how the data should be processed. All C declarations and

statements must end with a semicolon.

Line 5 printf is a predefined function. To sent output on the monitor,

the text is put within the function parentheses and bounded by

quotation marks. The definition of this function is defined in the

STDIO library (the Standard Input/output library). To compile and

link this program the #include statement is required. The end result

is that whatever is included between the quotation marks in the

1. //sample program 2. #include "stdio.h" 3. void main() 4. {

printf ("This is a line of text to output.\n"); 5. }


15




printf function will be displayed on the monitor when the program is

run. Notice the semi-colon at the end of the line. C uses a semi-

colon as a statement terminator, so the semi-colon is required as a

signal to the compiler that this line is complete.

Line 6 The closing (right) brace marks the end of the main body of

the program.

1.10 Chapter summary

1.11 Chapter exercise

1.12 Further reading suggestion

Documents

Introduction to Programming & 2 Student registration & introduction to the module Introduction to programming methodology Programming language levels Factors to consider while selecting