1. CHAPTER 1: Introduction to Computers and Programming
CSEB113 PRINCIPLES of PROGRAMMING CSEB134 PROGRAMMING I by
Badariah Solemon
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2. Topics Overview of PC components Programming languages
C programming language
C programming environment
C program at a glance
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3. Overview of PC components
Topic 1
Overview of PC components
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4. Elements of a Computer Hardware Software Program? 3 2 1 4 5 2 1
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5. Main Memory
A semiconductor device which stores the information necessary for a program to run.
Types:
ROM (Read Only Memory)
Contains information that is necessary for the computer to boot up
The information stays there permanently even when the computer is turned off.
RAM (Random Access Memory)
Contains instruction or data needed for a program to run
Got erased when the computer is turned off.
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6. Anatomy of Main Memory
Memory may be conceptually viewed as an ordered sequence of storage location called memory cells.
Information is stored in memory in bits
A memory cell is a group of bits called a byte
Each memory cell has a unique address A9 A8 A7 A6 A5 A4 A3 A2 A1 B9 B8 B7 B6 B5 B4 B3 B2 B1
Ref: Tan and D’Orazio, C Programming for Engineering & Computer Science, New York: McGraw-Hill
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7. CPU Does most of the work in executing a program
The CPU inside a PC is usually the microprocessor
Three main parts:
Control Unit
Fetch instructions from main memory and put them in the instruction register
ALU (Arithmetic Logic Unit)
Execute arithmetic operations
Registers
Temporarily store instructions or data fetched from memory
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8. Secondary Storage Devices
Magnetic devices used to store a large amount of information.
Store the software components or data needed for the computer to execute its tasks.
Could be “read only” or “writable”.
Example:
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9. Input/Output Devices Input Devices Output Devices
Accepts information from the user and transforms it to digital codes that the computer can process
Example:
Output Devices
An interface by which the computer conveys the output to the user
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10. Computer Networks
Computers are now linked together in networks – communicate
Types:
LAN ( )
Computers and other devices in a building are connected by cables or wireless network
WAN ( )
Links many individual computers and LANs over a large geographic area
The most well-known WAN is _____________
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11. Software
Consists of programs that enable us to solve problems with a computer
Operating Systems
Utility Programs
Language Translation
System Software
Application Software
*Complete this list
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12. programming languages
Topic 2
programming languages
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13. What is Programming?
Programming is instructing a computer to do something for you with the help of a programming language
A programming language contains instructions for the computer to perform a specific action or a specific task:
'Calculate the sum of the numbers from 1 to 10‘
'Print “I like programming”‘
'Output the current time'
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14. What is Programming?
Programming Language is different compared to our everyday-language (natural language); spoken and written
Does not have to be 100% but still understandable
Depends on circumstances; the context – one word can have many meaning depending on the situation
For example:
OPERATE
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15. What is Programming? The two roles of a programming language:
Technical: It instructs the computer to perform tasks.
Conceptual: It is a framework within which we organize our ideas about things and processes.
In programming, we deal with two kind of things:
Data - representing 'objects' we want to manipulate
Procedures -'descriptions' or 'rules' that define how to manipulate data
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16. Programming Language
Programming Language is a Formal Language used to communicate to a computer.
Very specific (one word means one thing – context free) since to 'talk' to a computer; to instruct a computer; our commands must be 100% clear and correct.
Either Functional - tell what to do but not how (sum [1...10])
or Imperative - describing the step by step to accomplish the task (Take the first number and add the next number to it; then add the next number to the sum; and …………; until you have reached 10 as number to be added. Then print the sum of all numbers)
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17. Programming Language
Can be classified into as a special-purpose and general-purpose programming languages.
Special-purpose : is design for a particular type of application
Structured Query Language (SQL)
General-purpose : can be used to obtain solutions for many types of problems
Machine Languages
Assembly Languages
High-Level Languages
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18. 1. Machine Language
The only language that the processor actually understand.
Consists of binary codes: 0 and 1
Example:
Each of the lines above corresponds to a specific task to be done by the processor.
Programming in machine code is difficult and slow since it is difficult to memorize all the instructions. Mistakes can happen very easily.
Processor dependent (different machine language for different CPU) - not portable
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19. 2. Assembly Language
Enable machine code to be represented in words and numbers.
Example of a program in assembly language:
LOAD A, 9999
LOAD B, 8282
Cannot be processed directly by a computer, must be converted to machine language using assemblers
Easier to understand compared to machine code but still is quite difficult to use.
Each instruction corresponds to a specific machine code: lengthy programs.
Processor dependent and not portable.
LOAD A, 9999
LOAD B, 8282
SUB B
MOV C, A
LOAD A, 9999
LOAD B, 8282
SUB B
MOV C, A
Assembler
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20. 3. High-level Language
Use more English words. They try to resemble English sentences so easier to program in these languages. Example:
printf (“Hello”)
The programming structure is problem oriented - does not need to know how the computer actually executes the instructions.
Processor independent - the same code can be run on different processors.
Needs to be analyzed by the compiler and then compiled into machine code so that it can be executed by the processor.
Example languages – Java, BASIC, C, C++
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21. C Programming language
Topic 3
C Programming language
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22. What is ‘C’?
Why ‘C’? - Because based on 'B'; developed at Bell Laboratories
C was developed by Dennis Ritchie at Bell Laboratories in 1972.
C combines the power of high-level languages with the power of assembly languages.
Starts as a system implementation language, but has evolved into general-purpose language and available for a wide variety of computers.
C coupled with good program design techniques - generate well structured, easy to read and easy to maintain program
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23. What is ‘C’?
In 1983, the American National Standards Institute (ANSI) set up X3J11, a Technical Committee to draft a proposal for the ANSI standard, which was approved in 1989 and referred to as the ANSI/ISO 9899 : 1990 or simply the ANSI C, which is now the global standard for C.
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24. C – An Imperative Language
C is a highly imperative language
We must tell it exactly how to do what;
the means and functions to use;
which libraries to use;
when to add a new line;
when an instruction is finished;
in short: everything and anything…
Hint: Observe the syntax in the next slide
Semantics – the meaning of the language within a given context
Syntax - Syntax are the rules to join words
together in forming a correct expression or phrase.
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25. Example of a C program function for printing a character/string
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*Complete the labeling

26. C Programming Environment
Topic 4
C Programming Environment
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27. IDE
The system software necessary to develop C application program are bundled into an integrated development environment (IDE)
A typical IDE contains text editor, C compiler, preprocessor, libraries, other tools
Components of C programming environment:
Language – features to carry out basic operations (Ex. Compare data values, arithmetic operation)
Libraries – routines to carry out operations not part of the language (Standard libraries – ex. #include <stdio.h> & programmer-defined libraries)
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28. Ms Visual C++
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29. Topic 5
C program at a glance
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30. A Simple C Program Output: CONSOLE VIEW of the C program’s output
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31. Summary PC components Programming languages
Hardware : main memory, CPU, storage devices, I/O devices
Software : system software & application software
Programming languages
Machine language, assembly language, high-level languages
C as a highly imperative language
A typical C programming environment
contains text editor, C compiler,
preprocessor, libraries, other tools
BS (May 2012)