ECE 1211: Object Oriented Programming for Engineers

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ECE 1211 Object Oriented Programming for
Engineers
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Todays lecture

• Course Outline
• Course Schedule
• Course Policy

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Course Objectives

• To introduce the concept of Object Oriented
  Programming and design
• To develop programming skills based on the Object
  Oriented paradigm using C
• To apply the Object Oriented Programming concept
  in engineering area

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Learning Outcomes

• Able to explain the concept of Object Oriented
  Programming
• Able to outline and apply the concepts of
  encapsulation, inheritance and polymorphism
• Able to design, code, test and debug simple
  program in Object Oriented Programming language
• Able to develop a simple project in a group

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I dont expect you to be like this!
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Assessment

• Assignments (15) and Quizzes (10) 25
  
• Project
  35
• Mid-term Examination 20
• Final Examination
  20
• TOTAL
  100

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Course Policy

• Please abide to all rules and regulations
• Attendance is compulsory
• 10 - warning letter, 20 barred from
  examination
• All information and materials
• http//staff.iiu.edu.my/afidalina
• Assignment must be submitted before the deadline.
  No late submission will be entertained. Both
  SOURCE and DESTINATION deserve ZERO mark
• I will not consider any absence from Mid
  Term/Project etc without any PRIOR notice
• I could hardly accept weird/illogical reasons
• Because that will reflect your attitude and
  commitment
• Class Representative
• Text book

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ICE BREAKING!
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Quiz 1
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Lets start our 1st real lecture
Introduction to C Part 1
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Introduction to C
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Objectives (1)

• Understand differences between C and C
• Skill to write simple program in C with
  standard I/O
• Understand namespace concept and usage
• Familiar with C standards

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What is a program?

• A sequence of instructions (program statements)
  to solve a problem
• Program statements (actions)
• Specific order of executions (algorithm)
• ?solve a problem

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C

• Supports only procedural programming concept
• Data and operations are two independent
  entity/unit
• (Computer) Program is viewed as a sequence of
  actions (program statements)
• Difficult to maintain integrity of data

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C

• Developed to overcome problems found in C
• Contains almost everything in C and other
  features to support efficient software (large and
  complex programs) development

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Additional features in C

• Supports object-oriented programming concept
  (to-be detailed through out the course).
  Particularly useful to develop large software
• Strict type checking to reduce the
  chances/probability of bug (error)
• Enhanced pointers, functions
• On-the-fly variable declaration
• Variables can be declared anywhere in the program
  (not necessarily at the beginning of it)

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C and C

• C is a superset of C

C
C
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Introduction to C

• We can write single line comment by using //
• Latest C compiler also support this feature
• Does not require the .h extension for standard
  libraries ( required for user defined libraries)
• Library collection of files that contain
  declarations and definitions of programming
  entities ( function, data types, constants, etc.)

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C Input/Output

• C uses scanf() and printf() to perform input and
  output
• C treats input/output operations as
• Keyboard as cin object of type istream
• Output terminal as cout object of type ostream
• Operators gtgt and ltlt to send streams to cout or
  read from cin.

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• / Welcome to C /
• include ltiostreamgt
• include ltstringgt
• //.h extension is not required for standard lib.
• using namespace std
• // std namespace
• int main()
• string name //variable declaration name of type
  string
• //prompt user to enter name
• cout ltlt " Please Enter your nick name "
• //read user name
• cin gtgt name
• //print out welcome message
• cout ltlt " Welcome to C ltlt" ltlt name ltlt "gtgt" ltlt
  endl

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• //PROG1_1 Program demonstrates C I/O.
• include ltiostreamgt
• using namespace std //cout and cin are defined
  in std
• int main()
• float length, width, area
• coutltlt"Enter length and width gt "
  //output
• cingtgtlengthgtgtwidth
  //input
• arealengthwidth
• coutltlt"Area "ltltarea
  //output
• return 0

• /Demonstration of I/O in C/
• includeltstdio.hgt
• int main()
• float length, width, area /variable
  declarations/
• printf("Enter length and width\n") //prompt
  user to input
• scanf("ff",length, width ) //read
  keyboard input
• area widthlength
• printf("Area f\n",area )
• return 0

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Data types

• Data types in C
• void (nothing)
• char A, 1, ? etc.
• int 1, 124, 999, etc.
• Variations short, long, unsigned
• float 123.44, 0.23, etc.
• double 123.44, 0.00000001
• bool true (logic 1), false (logic 0)

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• // Examples of boolean usage
• includeltiostreamgt
• using namespace std
• int main()
• bool x,y,z
• cout ltlt"Simulate XOR gate \n"
• cout ltlt"Enter two logic values \n"
• cin gtgt x gtgt y
• cout ltlt "The XOR of " ltlt x ltlt"," ltlt y ltlt ""
  ltlt (x y) ltlt endl
• return 0

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Data type conversion

• Using various data types in the same program is
  common
• Need to perform operation involve mixed data
  types
• Need to convert between data types
• Automatic conversion
• Values of different data types (in an expression)
  are first converted to the largest one then the
  expression is evaluated
• A r.h.s value is converted to the data type of
  l.h.s

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It may become a source of logic error

• // Demonstrate automatic conversion between data
  types
• includeltiostreamgt
• using namespace std
• int main()
• int a2
• short a222
• double b3.14156, x
• x ab
• a b
• cout ltlt a ltlt '\t' ltlt b ltlt '\t' ltlt x ltlt endl
• return 0

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Explicit conversion

• C-style cast
• (new type) var
• (float) x
• C style cast
• Standard data type conversion
• static_castltnew typegt ( var )
• To remove const-ness of a function argument
• const_cast
• User-defined (class) type conversion
• reinterpret_castltnew typegt (object)

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• // Demonstrate Explicit conversion between data
  types
• includeltiostreamgt
• using namespace std
• int main()
• int a10
• double b, d
• b (double) a //C-style casting
• d static_castltdoublegt (a) //C style
  casting
• cout ltlt a ltlt '\t' ltlt b ltlt'\t' ltlt d ltlt endl
• const int aa a //declaring const reference
• cout ltlt aa ltlt endl
• const_castltintgt(aa) 7
• cout ltlt aa ltlt endl

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Variables scope

• Scope is the program portion/part where a
  variable can be referenced
• Global scope
• A variable can be referenced anywhere in the
  program
• Local scope
• A variable can be referenced only in the portion
  where it is declared

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Global variable in C

• C allows the same identifier to be used as
  global and local variables names simultaneously
  (at the same time)
• Distinguished by (scope resolution operator)

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• // Scope of variables
• includeltiostreamgt
• using namespace std
• int x111 //declare global variable x
• int main()
• int x 222 //declare local variable x
• int x 333
• //declare yet another local variable having
  block scope
• cout ltlt "X in the block is " ltlt x ltlt endl
• cout ltlt "X in the main is " ltlt x ltlt endl
• cout ltlt "Global value of x is " ltlt x ltlt
  endl
• return 0

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I/O formatting

• In C programmers have to specify the format of
  any input/output operation
• int x
• printf(the value of x is d\n, x )
• C type formatting is automatic for build in
  data types
• int x
• cout ltlt the value of x is ltlt x ltlt endl

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Manipulating I/O

• Manipulate base of numbers
• Oct, hex, dec
• Manipulate character controls
• Newline ch., null ch., etc
• Manipulate format control
• Requires ltiomanipgt header file
• setw(int) field width for a single output field
• setprecision(int) floating point precision
• Refer to references for more detailed explanation

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• //PROG1_2 Program demonstrates C formatting.
• include ltiostreamgt
• include ltiomanipgt
• using namespace std
• void print()
• coutltlthexltltsetw(5)ltlt11ltltendl
• int main()
• coutltltsetw(20)ltlt"C FORMATTING"ltltendl
• coutltlt"Integer numbers\n"
• coutltlt173ltltendl
• print()
• coutltltsetiosflags(iosleftiosuppercase)
• coutltltsetw(6)ltlt15ltltdecltlt15ltltendl
• coutltlt"\nFloating point numbers"ltltendl

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Namespace

• Large program/software may consist of separate
  files
• An entity where we can declare variables, define
  functions, etc. to avoid name conflict or clashes
• E.g., namespace std contains the declaration of
  object cin, cout, cerr and clog that we used for
  I/O operation

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• //PROG1_4 Program demonstrates using directives.
  
• include ltiostreamgt
• using namespace std //predefined namespace
• namespace Rectangle //user-defined
  namespace
• float length
• float width
• void area() coutltlt"Area "ltlt(lengthwidth)
  
• using namespace Rectangle //Specifies
  user-defined namespace
• int main()
• coutltlt"Enter length gt "
• cingtgtlength
• coutltlt"Enter width gt "
• cingtgtwidth
• area()
• return 0

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• //PROG1_5 Program demonstrates code without the
  using directive.
• include ltiostreamgt
• namespace Rectangle
• float length
• float width
• void area() stdcoutltlt"Area
  "ltlt(lengthwidth)
• int main()
• stdcoutltlt"Enter length gt "
• stdcingtgtRectanglelength
• stdcoutltlt"Enter width gt "
• stdcingtgtRectanglewidth
• Rectanglearea()
• return 0

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Summary

• Are you familiar with C syntaxes now?
• C provides more facilities for programmers
• New data type
• Ease of I/O operation
• Scope of variables
• Global or local
• Global variables can be accessed by using
• More facilities to manipulate I/O
• Requires ltiomanipgt library

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Pointers, References and Dynamic Memory
Allocation and Array
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Objectives (2)

• To understand the differences between C and C
  pointers
• To familiarize reference data type
• To be able to allocate and release (deallocate)
  memory dynamically
• new operator to allocate memory
• delete operator to deallocate memory
• To appreciate the benefit of dynamic memory

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Why pointers?

• Many says pointer is difficult to master
• It is useful to write program efficiently
• by dynamic memory allocation
• Modification through functions
• To support some data structures such as linked
  list, binary tree

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Pointers

• Pointer is variable that contains memory address
  of any of the following
• Variable
• Pointer
• Function

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Pointer declaration

• Pointer to variable
• Type var
• double x
• void y
• Pointer to another pointer
• double z
• double x z
• double y x
• Operators
• is called indirection (dereferencing) operator
• is called address-of operator

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• // Pointer declarations
• includeltiostreamgt
• using namespace std
• int main()
• double z 3.1415
• double y z //declare a pointer to
  variable
• double x y //declare a pointer to
  pointer. note the
• //double v 10 //error 10 is an int
  literal, not variable
• //int ptr z // z is not an integer
• //double ptr2 z //pointer must be
  initialized with address
• cout ltlt z ltlt"\t" ltlt y ltlt "\t" ltlt x ltlt endl
• system("pause")
• return 0

0x200
x
0x220
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Pointer declaration

• double x //non-const variable
• double ptr x // non-const pointer to
  non-const variable
• const double ptr2 x2 //non-const pointer to
  const variable
• const double const ptr3 x2 //const pointer
  to const variable
• double const ptr4 x //const pointer to
  non-const

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• /const pointer and const variable /
• includeltiostreamgt
• using namespace std
• int main()
• int x 10 //non-const variable
• int y -100
• int ptr1 x //pointer to integer
• const int ptr2 x // pointer to const
  integer
• const int const ptr3 x // const pointer
  to const integer
• int const ptr4 x //const pointer
• cout ltlt "x " ltlt x ltlt endl
• cout ltlt "ptr1 " ltlt ptr1 ltlt " ptr2 " ltlt
  ptr2 ltlt " ptr3 " ltlt ptr3 ltlt endl
• ptr1 100
• cout ltlt "ptr1 " ltlt ptr1 ltlt " ptr2 " ltlt
  ptr2 ltlt " ptr3 " ltlt ptr3 ltlt endl
• //ptr2 1000 //error. try to modify a read
  only location

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Reference

• It is an alternative name of other variable of
  the same type. (an alias?)
• It must be initialized during declaration
• type var var2
• int y 10
• int z y //declare reference variable z
• //which is initialized to y

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• //PROG3_1 Program demonstrates a use of an
  independent
• // reference variable.
• include ltiostreamgt
• using namespace std
• int main()
• int i 13
• int iref i //declaring a reference
  variable
• coutltlt"The value is gt "ltltiref
• i--
• coutltlt"\nAfter decrementing gt "ltltirefltltendl
• iref 99
• coutltlt"The value is now gt "ltlti
• return 0

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Static and Dynamic Array

• Static array
• Memory must be allocated during the compilation
  of the program
• Fixed during the execution of the program
• If less space is used ?waste of memory
• If more space is used ?may cause crash
• Dynamic array
• Memory can be allocated dynamically during run
  time (execution)
• The size varies
• Efficient usage of memory

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• // Program demonstrate static array and pointer
• includeltiostreamgt
• using namespace std
• int main()
• const int SIZE 50
• int markSIZE 0
• int input
• int count 0
• cout ltlt "Enter grade 0-100" ltlt endl
• while((cingtgtinput))
• if( (inputlt0) (inputgt100) )
• cout ltlt"Out of range " ltlt endl
• else
• markcount input
• count

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• //PROG3_4 Program demonstrates a
  single-dimensional
• // dynamic array.
• include ltiostreamgt
• include ltiomanipgt
• using namespace std
• int main()
• int ptr
• int SIZE
• coutltltNumber of data?"
• cin gtgt SIZE
• ptr new intSIZE //Allocates an array
  dynamically
• if(!ptr) //Checks for a memory
  allocation error
• coutltlt"Memory allocation error!"
• exit(1)
• for(int i0 iltSIZE i)

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Connecting pointer and array

• Array name is the address of the array (address
  of the first element)
• Pointer can point to array
• int array10
• int ptr
• ptr array // not ptr array
• ptr array0 //equivalent to the above

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• //Relate a pointer to an array
• includeltiostreamgt
• using namespace std
• int main()
• int array100
• int array2 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
• int ptr
• ptr array
• for( int a0 alt10 a )
• cout ltlt arraya ltlt"\t" ltlt ptra ltlt"\t" ltlt
  (arraya) ltlt "\t" ltlt (ptra) ltlt endl
• ptr array2
• for( int a0 alt10 a )
• cout ltlt array2a ltlt"\t" ltlt ptra ltlt"\t" ltlt
  (array2a) ltlt "\t" ltlt (ptra) ltlt endl
• system("pause")
• return 0

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Notes on Pointer and Reference

• Make sure that you do not try to access array
  beyond its boundary (size)
• Array index starts from zero not one
• Can not assign one array to another (a b )
• Char array is a special array
• Ended with a \0 null character
• The whole array can be printed at once by using
  stream insertion operator
• Use class string
• We will revisit them again when we discuss
  function

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Summary

• Pointer is variable containing memory address
• Reference is variable which is an alias of
  other variable
• When a pointer points to an array pointer name
  and array name are compatible
• Dynamic memory allocation is important to write
  efficient program
• new operator to allocate memory
• delete operator to de-allocate memory