Introduction - Programming Using C Sharp - Lecture Slides, Slides of Advanced Algorithms

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IT 519

Introduction to Programming Using

C#

Gülşen Demiröz

Summary of the Course

• Introduction to programming and

algorithms

• We will learn how to develop object

oriented programs using the C#

programming language on Microsoft ® .NET

Platform

• We will also learn few classes from the

Microsoft ® .NET Framework Library as

needed

Example Algorithm - Find the minimum

• Initial list: 4 6 7 3 9 1 4 5
• Should we sort? 1 3 4 4 5 6 7 9
  • The minimum is the first one
• Optimal algorithm - About n operations
  • Pick 4 as the minimum
  • Compare 4 to 6 - min is still 4
  • Compare 4 to 7- min is still 4
  • Compare 4 to 3 - Pick 3 as the minimum
  • Compare 3 to 9- min is still 3
  • Compare 3 to 1 - Pick 1 as the minimum
  • Compare 1 to 4- min is still 1
  • Compare 1 to 5 - We are done and the minimum is 1

Basic Program Development Steps

Analyze Problem

Develop Algorithm

Design Program

Write pseudo- code on paper

Code over the computer

Source Code

Compile & Build

Syntax Errors?

Yes

Correct it

No Run

Correct Results?

Yes - Done

No

Correct (Debug)

Programming Languages

• We solve problems with algorithms
• Then we use computers to run these algorithms
• For this, we need programming languages to interact with the computer’s hardware
• Computers represent data in numeric format
  • Internal representation (at the lowest level) is in binary form: 0 and 1 (4=100, 5=101)
  • 0 and 1’s are stored in a bit, 8 bits is called a byte
• Programs are set of instructions that process data
• These low level instructions are also in binary (0 and 1)
  • machine language: not human readable and programmable!
• Rather than instruct computers at the level of 0’s and 1’s, higher level languages have been developed. - Flexible and easier programming
• Compilers translate a high level language, such as C , into machine-specific executable program (0 s^ and 1 s^ )

C, C++ and Java

• C first gained widespread recognition as the development

language of the UNIX operating system.

• C++ took the C language and provided capabilities for object-

oriented programming (OOP).

• Objects are reusable software components that model items

in the real world.

• Object-oriented programs are often easier to understand, correct and modify.
• Sun Microsystems began development of the Java

programming language in 1991.

• Java is now used to develop large-scale enterprise applications.

8

.NET Platform

• Provides programmers to develop their components in

any language and easily share them (old way: COM).

• Very rapid development with the help of already built-in

classes or platforms.

• Applications in any .NET-compatible language can interact

with each other.

• The .NET strategy allows programmers to concentrate on

their specialties without having to implement every

component of every application.

• End to DLL hell with versioning.

Compiling

code.cpp

Assembly language

Machine language .exe

C/C++

old languages

C#

.NET languages

compiling

code.cs

Intermediate Language (MSIL)

• metadata

Machine language .exe

C# compiler

JIT compiler

code.vb

VB.NET compiler

Common Language Runtime (CLR)

Automatic Memory Management

• One of the services that the common language

runtime provides during Managed Execution.

• Allocation and releasing of memory is managed by the

CLR: Garbage collection.

• No more memory leaks 

Visual Studio 2008

• Fast Integrated Development Environment

(IDE)

• Very good user interface (UI) design

– easy to find compiler errors and debugging

• Heavy visual support to develop UI

• Let’s install it, detailed instructions on

course’s web site:

http://myweb.sabanciuniv.edu/gulsend/su_current_courses/it519/