CS141 Lecture 1 (1)

7/31/2019 CS141 Lecture 1 (1)

1/28

7/31/2019 CS141 Lecture 1 (1)

2/28

CS-141

Programming Fundamentals

Jameel Ahmad

Assistant [email protected]

Department of Electrical EngineeringUniversity of Management and Technology

CS141-Programming Fundamentals
mailto:[email protected]:[email protected]

7/31/2019 CS141 Lecture 1 (1)

3/28

Text Book for the course

Required Textbook:

C How to Program 5th or 6th edition

Paul Deitel and Harvey Dietel


7/31/2019 CS141 Lecture 1 (1)

4/28

Grading Policy

Labs (attendance + task completion): 20%

Quizzes : 10%

Assignments: 15%

Mid Term: 15%

Final Exam (Code + Conceptual): 40%


7/31/2019 CS141 Lecture 1 (1)

5/28

Student Civility In an effort to make this class enjoyable foreverybody

Please be on time to class!

Please do not talk to your friends and neighbors inclass! It disturbs everyone, and makes it hard toconcentrate. If you have a question, just ask me!

Please turn your pagers and cell-phones off!

5CS141-Programming Fundamentals

7/31/2019 CS141 Lecture 1 (1)

6/28

Help is always available

Option 0: Send me an SMS thatyou want to discuss some issue Option 1: Come to my Office

Hours

Option 2:Send me an email

6

7/31/2019 CS141 Lecture 1 (1)

7/28

Course Description Introduction to algorithms and programming

What is an algorithm?

What is programming?

Programming philosophy How to think of a programming problem

How to plan the solution to the problem Problem decomposition

Top-down refinement


7/31/2019 CS141 Lecture 1 (1)

8/28

Course Description (2) Using an interactive development environment (IDE)

Types of programming errors Syntactic

Semantic

Using a structured programming language What is a programming language?

What is a structured programming language?


7/31/2019 CS141 Lecture 1 (1)

9/28

Course Description (3) Main language concepts covered:

Simple data types

Numbers (integer, real)

Boolean

Characters Strings

(NOT structured/complex data types)

Input / output statements

Basic statements (assignment, conditionals,iteration/looping)


7/31/2019 CS141 Lecture 1 (1)

10/28

Course Objectives Understand basic components in a computer

architecture

Appreciate the role of programming languages

Design a top-down solution for solving problems

Be familiar with an IDE

Edit, compile, debug and run short programs


7/31/2019 CS141 Lecture 1 (1)

11/28

Outline of Topics Hardware/Software interface

Layers of the Machine

Kinds of Software Computer Languages

Syntax, Semantics, Grammars

What happens to your program?

Compilation, Linking, Execution

Program errors

Compilation vs. Interpretation etc.


7/31/2019 CS141 Lecture 1 (1)

12/28

Software CategoriesSystem SW

Programs written for computer systems

Compilers, operating systems,

Application SWPrograms written for computer users

Word-processors, spreadsheets, & otherapplication packages


7/31/2019 CS141 Lecture 1 (1)

13/28

A Layered View of the Computer

Machine with all its hardware

System SoftwareCompilers, Interpreters,Preprocessors, etc.

Operating System, Device Drivers

Application Programs

Word-Processors, Spreadsheets,

Database Software, IDEs,

etc


7/31/2019 CS141 Lecture 1 (1)

14/28

Operating System (OS) Provides several essential services:

Loading & running application programs

Allocating memory & processor time Providing input & output facilities

Managing files of information


7/31/2019 CS141 Lecture 1 (1)

15/28

Programs Programs are written in programming languages

PL = programming language

Pieces of the same program can be written in differentPLs Languages closer to the machine can be more efficient

As long as they agree on how to communicate

A PL is

A special purpose and limited language

A set of rules and symbols used to construct a computerprogram

A language used to interact with the computer


7/31/2019 CS141 Lecture 1 (1)

16/28

Computer Languages

Machine Language Uses binary code Machine-dependent Not portable

Assembly Language Uses mnemonics Machine-dependent Not usually portable

High-Level Language (HLL) Uses English-like language Machine independent Portable (but must be compiled for different platforms) Examples: Pascal, C, C++, Java, Fortran, . . .


7/31/2019 CS141 Lecture 1 (1)

17/28

PL hierarchy


7/31/2019 CS141 Lecture 1 (1)

18/28

Machine Languages, Assembly Languages,

and High-level Languages Three types of programming languages

Machine languages Strings of numbers giving machine specific instructions

Example:

+1300042774 (these would really be in binary)+1400593419

+1200274027

Assembly languages English-like abbreviations representing elementary

computer operations (translated via assemblers) Example:

LOAD BASEPAY

ADD OVERPAY

STORE GROSSPAY

2000 Prentice Hall, Inc. All rights reserved.

18CS141-Programming Fundamentals

7/31/2019 CS141 Lecture 1 (1)

19/28

Machine Languages, Assembly Languages,

and High-level Languages High-level languages

Instructions closer to everyday English English is a natural language. Although high level

programming languages are closer to natural languages, it isdifficult to get too close due to the ambiguities in naturallanguages (a statement in English can mean different things todifferent people obviously that is unacceptable for computerprogramming). However, this is a big research area ofcomputer science.

Use mathematical notations (translated via compilers)

Example:grossPay = basePay + overTimePay

Interpreter Executes high level language programs withoutcompilation.

2003 Prentice Hall, Inc. All rights reserved.

19(modified by Evan Korth)


7/31/2019 CS141 Lecture 1 (1)

20/28

Machine Language The representation of a computer program which is

actually read and understood by the computer. A program in machine code consists of a sequence of machine

instructions.

Instructions:

Machine instructions are in binary code Instructions specify operations and memory cells involved in the

operation

Example: Operation Address

0010 0000 0000 0100

0100 0000 0000 0101

0011 0000 0000 0110


7/31/2019 CS141 Lecture 1 (1)

21/28

7/31/2019 CS141 Lecture 1 (1)

22/28

High-level language A programming language which use statements consisting

of English-like keywords such as "FOR", "PRINT" or IF, ...etc.

Each statement corresponds to several machine languageinstructions (one-to-many correspondence).

Much easier to program than in assembly language.

Data are referenced using descriptive names

Operations can be described using familiar symbols Example:

Cost := Price + Tax


7/31/2019 CS141 Lecture 1 (1)

23/28

Attributes of a good language Clarity, simplicity, and unity

Have a minimum number of different concepts, withthe rules for their combination, simple and regular

(conceptual integrity). readability

Orthogonality Being able to combine various features of a language in

all possible combinations. Naturalness for the application

Support for abstraction


7/31/2019 CS141 Lecture 1 (1)

24/28

Attributes of a good language Ease of program verification

Proof of correctness, desk checking, test

Simplicity of semantic and syntax

Programming environment

Portability of programs

Cost of use

Program execution Program translation

Program creation, testing, and use

Program maintenance


7/31/2019 CS141 Lecture 1 (1)

25/28

Attributes of a good language(another view: to make a software reliable,

maintainable, efficient) Reliability

Writability

Readability

Simplicity

Safety (no goto, no pointers)

Robustness (undesired events can be trapped, likearithmetic overflow, invalid inputs)

Maintainability Factoring (modularity)

Locality

EfficiencyCS141-Programming Fundamentals

7/31/2019 CS141 Lecture 1 (1)

26/28

Syntax & Semantics Syntax:

The structure of strings in some language. A language'ssyntax is described by a grammar.

Examples: Binary number

= | = 0 | 1

Identifier = { | }

= a | b | . . . | z

7/31/2019 CS141 Lecture 1 (1)

27/28

7/31/2019 CS141 Lecture 1 (1)

28/28

Syntax & Grammars Syntax descriptions for a PL are themselves written in

a formal language.

E.g. Backus-Naur Form (BNF)

The formal language is not a PL but it can beimplemented by a compiler to enforce grammarrestrictions.

Some PLs look more like grammar descriptions thanlike instructions.

CS141 Programming Fundamentals

CS141 Lecture 1 (1)

Documents

Transcript of CS141 Lecture 1 (1)