Introductory programming with c
Download
1 / 43

- PowerPoint PPT Presentation


  • 123 Views
  • Updated On :

Introductory Programming with C#. Judith Bishop University of Pretoria, South Africa Visiting TU-Berlin. Talk overview. Introduction Who, why, when, how, with what? Syntax and semantics for you and your students A tour through some lessons Early concepts Our approach to GUIs Debugging

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '' - gaille


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Introductory programming with c l.jpg

Introductory Programmingwith C#

Judith Bishop

University of Pretoria, South Africa

Visiting TU-Berlin

Microsoft Courses 2003


Talk overview l.jpg
Talk overview

  • Introduction

    • Who, why, when, how, with what?

  • Syntax and semantics

    • for you and your students

  • A tour through some lessons

    • Early concepts

    • Our approach to GUIs

    • Debugging

    • Advanced concepts

  • Assessment

    • Quizzes, exercises, laboratories, exams

  • References

Microsoft Courses 2003


Featuring l.jpg
Featuring …

  • Syntax and semantics descriptions

  • Early use of libraries

  • Independent GUI specifications

  • Debugging

New

Microsoft Courses 2003


Focus on c l.jpg
Focus on C#

  • Designed by Anders Hejlsberg, Scott Wiltamuth and Peter Golde

  • To b the main development medium for future Microsoft products

  • Origins in C++, Java, Delphi, Modula-2, Smalltalk

  • Heljsberg was the chief architect behind Turbo Pascal and Delphi

  • Standardised by Ecma and ISO

  • Free (to us)

Microsoft Courses 2003


Changing languages l.jpg
Changing languages

  • Major movements worldwide

    • To Pascal in 1970s and 1980s

    • To Java in 1990s

  • Caused by advances in technology

    • Data structures, oops, internet computing

    • Foundation for later courses

    • Desire to be "ahead of the pack"

  • Inhibitors to change

    • Lack of teaching resources

    • Computing resources required by new technology

    • Investment in current language

    • Uncertainty over the measure of improvement

Microsoft Courses 2003


A first programming course l.jpg
A first programming course

  • Typically 40-50 lectures

  • 10-14 laboratories

  • Take home assignments

  • Project

  • Questions:

    • where does it start?

    • where does it end?

    • what is the place of libraries?

    • what is the order of topics?

    • what should be included/left out?

    • what do I need to run the language?

Microsoft Courses 2003


Where does it start and end l.jpg
Where does it start and end?

  • Most institutions assume "no background"

    • most students have more than that

    • use of computers is almost universal now

    • students can interact with GUIs

  • Strong desire to have "objects first"

    • but what is second?

    • what do objects assume?

  • With or without GUIs?

    • huge tension between need to program realistically and the number of concepts required to express GUIs

  • Advanced topics can be left to other courses

    • networking and databases - NetCentric Computing

    • generics and overloading - Data Structures

Microsoft Courses 2003


What about libraries l.jpg
What about libraries?

  • Libraries cannot be ignored,

    • More in the libraries than in the language!

    • Without them, examples will be too constrained

  • Students can be on a "need to know basis", BUT they need to know the structure and organisation of libraries

    • This knowledge transcends languages

  • Early use of libraries introduces many fundamental concepts in a controlled manner, e.g.

    • variables vs properties

    • instance vs static

    • constructors

    • parameters

Microsoft Courses 2003


An order of topics l.jpg
An order of topics

  • Introduction to computers, languages and compiling 2

  • Using types 5

  • Defining types 5

  • Data structures and control structures 5

    Views System 4

  • Input and output with files 4

    Debugging 3

  • Collections 5

  • Extensibility and polymorphism 5

  • Extra topics 2

Half way

Microsoft Courses 2003


What to include l.jpg
What to include?

  • If a feature is covered, cover it completely, albeit over time in a spiral fashion

  • Include

    • images as data types - adds to the fun

    • GUIs - for realism

    • formatting and unicode - promotes internationalisation

    • serialization - makes for serious programs

    • exception handling - makes for robust programs

    • foreach loop - so neat and powerful

    • collections - enhance object-orientation

Microsoft Courses 2003


What to exclude l.jpg
What to exclude?

  • What to exclude depends on

    • length of course

    • interface with other courses

  • A suggestion

    • threads - in Operating Systems

    • networking - for Netcentric Computing

    • graphics and delegates - to introduce non-Views GUIs

    • operator overloading, other upcoming features (e.g. generics), - in Data Structures

  • Notes:

    • Topics that were in a Java introductory course might not be in a C# version (applets)

    • NOTE: some institutions will start with Netcentric Computing - interesting approach

Microsoft Courses 2003


What resources do i need l.jpg
What resources do I need?

  • Microsoft Academic Alliance, plus

  • Option 1 (Student):

    • a PC

    • C# compiler

    • Any simple editor

  • Option 2 (Lecturer)

    • a PC with lots of memory

    • Visual Studio

  • Option 3 (Researcher)

    • PC or Mac, Windows or Linux

    • Rotor

    • Any simple editor

Microsoft Courses 2003


C concisely l.jpg
C# Concisely

  • First year programming text book, Oct 2003

  • Pearson, 2004

  • Incorporates Views

  • Reviewed by Microsoft

  • Contents on the Views website

    http://csharp.cs.uvic.ca

Microsoft Courses 2003


Volunteers on a c course in africa l.jpg
Volunteers on a C# course in Africa

Do it in C# Naturally!

Microsoft Courses 2003


From the ecma c specification l.jpg
From the ECMA C# Specification

8.7.4 Properties

A property is a member that provides access to a characteristic of an object or a class. Examples of properties include the length of a string, the size of a font, the caption of a window, the name of a customer,and so on. Properties are a natural extension of fields. Both are named members with associated types, and the syntax for accessing fields and properties is the same. However, unlike fields, properties do not denote storage locations. Instead, properties have accessors that specify the statements to be executed when their values are read or written.

Properties are defined with property declarations. The first part of a property declaration looks quite similar to a field declaration. The second part includes a get accessor and/or a set accessor. In the example below, the Button class defines a Caption property.

public class Button {

private string caption;

public string Caption {

get {

return caption;

}

set {

caption = value;

Repaint();

}

}}

Microsoft Courses 2003


Syntax forms in c c l.jpg
Syntax forms in C#C

Fixed words

and symbols

Items to

fill in

public string Course {

get {return course;}

}

Microsoft Courses 2003


Also for libraries l.jpg
Also for libraries

Microsoft Courses 2003


Visual studio help l.jpg
Visual Studio Help

Microsoft Courses 2003


Concepts for simple oops l.jpg
Concepts for simple oops

Microsoft Courses 2003


Example sequence from early lessons l.jpg
Example sequence from early lessons

  • Example 2.5 (page 45) - Meeting times

    • Creates objects of type DateTime and accesses their properties and methods

  • Example 2.6 (page 47) - Dates in different formats

    • Further example of DateTime methods, customising output

  • Example 2.7 (page 49) - Time with reading

    • Introduces input using Console and the Parse methods of a type

  • Example 3.4 (page 83) - Table of meeting times

    • Using a loop to create different times

  • Examples 3.2 and 3.3 (page 75) - The shuttle bus

    • Defining a type from scratch and using it in a program

Microsoft Courses 2003


Slide21 l.jpg
GUIs

  • Current approaches do not emphasise independent principles

    OPTIONS

  • Create GUIs by hand

    • error prone

    • takes too much time

  • Use a GUI builder

    • dumps code in the program

    • hides principles

Microsoft Courses 2003


Where guis are going l.jpg

Views

Where GUIs are going

The reality of a

single cross-language,

cross-platform

GUI interface programming model

is in sight, based on an

XML description language

supported by

fast native runtimes.

[Russel Jones, DevX, Nov 2002]

Microsoft Courses 2003


And more recently l.jpg
… and more recently

Supporting many GUIs

isn't just a simple process

of including one set of libraries or another;

it's often a frustrating and error-prone exercise

in writing GUI-specific code.

[Russel Jones, DevX, Aug 2003]

Microsoft Courses 2003


Slide24 l.jpg

JScript

C#

Rotor CLI Implementation

VS.NET

System.Web

(ASP.NET)

System.WinForms

System.WinForms

System.Drawing

System.Data

(ADO.NET)

System.Xml

SDK Tools

System

Common Language Runtime

Platform Abstraction

Microsoft Courses 2003


Views l.jpg
Views

  • Views is a Vendor Independent Extensible Windowing System

  • Developed by Nigel Horspool and Judith Bishop with help from students in 2002-2003

  • Provides an XML-based specification notation for defining GUIs, and an execution engine for handling event listening and dispatching back to the program

  • It was supported under the Microsoft Rotor RFP Program

  • It is distributed from the C# Concisely book website

Microsoft Courses 2003



Example in winforms l.jpg
Example in WinForms

show.Click += new

EventHandler(ActionPerformed);

hide.Click += new

EventHandler(ActionPerformed);

}

public void ActionPerformed(Object src,

EventArgs args) {

if (src == show) {

pic.Show();

} else if (src == hide) {

pic.Hide();

}

}i

  • Embedded in 115 lines of generated code - “do not touch”

  • Unexplained classes and unused objects here

Microsoft Courses 2003


Gui building today l.jpg

widget rendering in the OS

widget calls in a language

Windows

GUI Builder

Application

Add Listeners

Handlers

Visual Studio

C#

GUI building today

Microsoft Courses 2003


A gui using xml l.jpg

widget rendering in the OS

GUI

XML

Spec

Application

Control Engine

Handlers

Add Listeners

A GUI using XML

Microsoft Courses 2003


Example in views l.jpg
Example in Views

XML

Views.Form f =

new Views.Form(@"<Form>

<vertical>

<horizontal>

<Button Name=Show/>

<Button Name=Hide/>

</horizontal>

<PictureBox Name=pic

Image='C:Jacarandas.jpg'

Height=175/>

</vertical>

</Form>" );

string c;

for (;;) {

c = f.GetControl();

PictureBox pb = f["pic"];

switch (c) {

case ”Show" : pb.Show();

break;

}

case ”Hide" : pb.Hide();

break;

}

}

}

C#

  • No pixel positioning

  • No generated code

  • Separation of concerns

Microsoft Courses 2003


Example 2 l.jpg
Example 2

Views.Form v = new Form (@"<form Text= Lucky>

<vertical>

<TextBox name =Number Text = '13'/>

<Button name = Start/>

<ListBox name = Day Width = 270/>

</vertical>

</form>");

int luckyNumber =

int.Parse(v.GetText("Number"));

Random r = new Random (luckyNumber);

for( ; ; ) {

string s = v.GetControl( );

if (s==null) break;

DateTime luckyDate =

new DateTime(DateTime.Now.Year, r.Next(3,12);, r.Next(1,30););

v.PutText("Day", "Your lucky day will be " +

luckyDate.DayOfWeek + " " + luckyDate.ToString("M"));

}

Microsoft Courses 2003


Other views examples l.jpg
Other Views examples

  • Calculator

    • Compare with text version

    • Separation of concerns

    • Internationalization

  • PhotoAlbum

    • Fun with pictures

Microsoft Courses 2003


Debugging l.jpg
Debugging

  • Principles - types of errors:

    • syntactic

    • semantic

    • runtime

  • Exception handling

  • Robust code

    • simple logic

    • validity checks - also with Assert

    • tracing statements

  • Debugger programs

    • Text based, or

    • GUI, with or without Visual Studio

Microsoft Courses 2003


Oops in c l.jpg
Oops in C#

  • Structs and classes

  • Well defined collection library

    • Array class

    • Sorted lists

    • BitArray

    • Queue, Stack, Hashtable

  • Polymorphism and extensibility

    • Interfaces and inheritance

Microsoft Courses 2003


Example access control l.jpg
Example - Access control

  • Page 318

  • Students, staff, posgrads and tutors have different rules for access to a building. The rules are implemented at the start of each year.

  • Polymorphic collection over IAccess

  • Classic simple data update example

  • Can be much extended e.g. for

    • serialisation

    • images

Microsoft Courses 2003


Assessment l.jpg
Assessment

  • Quizzes

    • available online on the website

  • Exercises

    • at the end of each chapter - answers will be provided to lecturers

  • Practicals

    • worksheets are being devised based on the book

  • Exam questions

    • samples will also be provided

      Watch for the CD

Microsoft Courses 2003


References l.jpg
References

  • Peter Drayton, Ben Albahari, Ted Neward, C# in a Nutshell, O’Reilly, 2002

  • Troelsen, Andrew “C# and the .NET platform” A! press 2001

  • Damien Watkins, Mark Hammond and Brad Abrams, Programming in the .NET environment, Microsoft .NET Development Series, Addison Wesley, 2002

  • Not many text books yet, but many trade books

  • Visual Studio help files

  • DevHood tutorials -- see http://www.devhood.com

  • http://www.cs.up.ac.za/rotor -- for the Views project

Microsoft Courses 2003


Motivation for a different approach l.jpg
Motivation for a different approach

  • Forward looking

    • Move to platform independent GUI systems

    • Integration of XML into languages (cf XEN)

  • Technical

    • Rotor does not have a GUI capability

    • Interesting challenges in Reflection, RegEx etc

  • Educational

    • Dissatisfaction with method-oriented or drag and drop GUIs

    • Separation of concerns

Microsoft Courses 2003


The views notation l.jpg
The Views Notation

form: <form>controlGroup</form>

controlGroup: <vertical>controlList</vertical>

| <horizontal>controlList</horizontal>

controlList: { control }

textItemList: { <item> text </item> }

control: controlGroup

| <Button/>| <CheckBox/>

| <CheckedListBox> textItemList </CheckedListBox>

| <DomainUpDown> textItemList </DomainUpDown>

| <GroupBox>radioButtonList</GroupBox>

| <Label/>| <ListBox/>

| <OpenFileDialog/> | <SaveFileDialog/>

| <PictureBox/> | <TextBox/>

| <ProgressBar/> | <TrackBar/>

radioButtonList: { <RadioButton/> }

Microsoft Courses 2003


Handler methods l.jpg
Handler methods

Essentially five kinds of methods:

construct

close

getControl

get

put

PLUS … direct access

Form(string spec,params)

The constructor.

void CloseGUI( )

Terminates the execution thread

string GetControl( )

Waits for the user to perform an action

string GetText(string name)

Returns the value of the Text attribute

int GetValue(string name)

Returns the Value attribute from TrackBar, ProgressBar and CheckBox

int GetValue(string name, int index)

Returns the status of CheckBox at position index

void PutText(string name, string s)

Displays the string in a TextBox or ListBox control.

void PutValue(string name, int v)

Sets an integer value associated with a ProgressBar or CheckBox

Microsoft Courses 2003


Handler methods41 l.jpg
Handler methods

Essentially five kinds of methods:

construct

close

getControl

get

put

PLUS … direct access

Form(string spec,params)

The constructor.

void CloseGUI( )

Terminates the execution thread

string GetControl( )

Waits for the user to perform an action

string GetText(string name)

Returns the value of the Text attribute

int GetValue(string name)

Returns the Value attribute from TrackBar, ProgressBar and CheckBox

int GetValue(string name, int index)

Returns the status of CheckBox at position index

void PutText(string name, string s)

Displays the string in a TextBox or ListBox control.

void PutValue(string name, int v)

Sets an integer value associated with a ProgressBar or CheckBox

Microsoft Courses 2003


Object orientation l.jpg

D1(P)

D2(Q)

D3(R)

F(D1) -- calls P

via M

F() -- calls M

F() -- calls M

I

D

A

M

M

M

A

B

A

C

B

B

C

P

Q

R

M

M

M

M

M

Object orientation

  • Extension, polymorphism

  • Delegation

C

Delegates

Interfaces

Inheritance

Microsoft Courses 2003


Gui building today43 l.jpg

widget rendering in the OS

widget calls in a language

Windows

GUI Builder

Application

Add Listeners

Handlers

Visual Studio

C#

GUI building today

Microsoft Courses 2003


ad