1. Intro to Programming Week # 1 Hardware / Software Lecture # 2
Department of Computer Science & Engineering
Air University
Intro to Programming Week # 1 Hardware / Software Lecture # 2
By: Saqib Rasheed

2. Computers Have Two Main Parts
Computer Hardware
Computer Software

3. What is Computer Hardware?
Computer Hardware is the physical part of the computer system, the machinery and equipment

4. Computer Software's
Computer Software are programs that tell the computer what to do.

5. What is a Computer? Computer Hardware Software
Device capable of performing computations and making logical decisions
Computers process data under the control of sets of instructions called computer programs
Hardware
Various devices comprising a computer
Keyboard, screen, mouse, disks, memory, CD-ROM, and processing units
Software
Programs that run on a computer

6. How to Communicate with computer?
Computer understands its own machine language (language of 0s and 1s).
Language instructs computer to perform tasks.
We need to understand computer’s language to communicate with it and to make it perform our desired functions.
So we have….

7. Programming Language
Set of rules and symbols used to construct a computer program
A language used to interact with the computer

8. Machine Languages, Assembly Languages, and High-level Languages
Three types of programming languages
Machine languages
Strings of numbers giving machine specific instructions
Example:
Assembly languages
English-like abbreviations representing elementary computer operations (translated via assemblers)
LOAD BASEPAY
ADD OVERPAY
STORE GROSSPAY

9. Machine Languages, Assembly Languages, and High-level Languages
Three types of programming languages (continued)
High-level languages
Codes similar to everyday English
Use mathematical notations (translated via compilers)
Example:
grossPay = basePay + overTimePay

10. What is C
C is a programming language developed at AT & T’s Bell Laboratories of USA in 1972.
It was designed and written by a man named Dennis Ritchie.
Influenced by
ALGOL 60 (1960),
CPL (Cambridge, 1963),
BCPL (Martin Richard, 1967),
B (Ken Thompson, 1970)

11. What is C….. Used to develop UNIX
Used to write modern operating systems
Hardware independent (portable)
C began to replace the more familiar languages of that time like PL/I, ALGOL, etc
Because it is reliable, simple and easy to use.

12. Steps in C/C++

13. The C++ Character Set
A character denotes any alphabet, digit or special symbol used to represent information.
We have 32 special symbols

14. Constants, Variables and Keywords
The alphabets, numbers and special symbols when properly combined form constants, variables and keywords.
A constant is an entity that doesn’t change.
Whereas a variable is an entity that may change.

15. Types of C Constants
C++ constants can be divided into two major categories:
Primary Constants
Secondary Constants
These constants are further categorized as shown in Figure

16. Program Errors Syntax errors
Related to the error in grammar/syntax of a language
Run time errors
during execution
indicate bugs
example: un-handled exceptions, memory overrun.
Logical errors
Bug in program that causes program to operate incorrectly, but not terminate.

17. Tools of the trade
Editor
Interpreter and Compilers
Debuggers

18. Integrated Development Environment (IDE)
It contains
Editor
Compilers
Debugger
Linkers
Loaders

19. Loader puts program in memory.
Preprocessor program
processes the code.
Loader puts program in memory.
CPU takes each
instruction and executes it, possibly storing new data values as the program executes.
Compiler creates object code and stores it on disk.
Linker links the object
code with the libraries
Loader
Primary Memory
Compiler
Editor
Preprocessor
Linker .
Disk
CPU
Program is created in the editor and stored on disk.