Introduction to C++ Programming Sessions 1-3

1. Introduction toC++ ProgrammingSessions 1-3 IT Learning Group

2. Today’s arrangements • Your teacher is: Ian Miller • Your demonstrators are: Chris, Hasan, Ronald • We finish at: 5:00pm • You should have: Class notes Copies of slides

3. Your safety is important • Where is the fire exit? • Beware of hazards • Tripping over bags and coats • Please tell us if anything does not work • Let us know if you have any other concerns

4. ♫♪ Your comfort is important • The toilets are along the corridor just outside the teaching rooms • The rest area is where you registered;it has vending machines and a water cooler • The seats at the computers are adjustable • You can adjust the monitors for height, tilt and brightness

5. What you know already… • Nothing is assumed

6. C++ and OOP? Compilers ISO and ANSI Standard C++ Library The Standard Template Library (STL ) Dev-C++ Today's Topics First Program Fundamental data types string class Functions

7. What is OOP? • Object Oriented Programming • A way of modelling individual objects in the real world • Students • Vehicles • Buildings • ATM’s • etc, etc

8. So, what is OOP? • Natural thinking – making our C++ code do what we expect something to do in real life. • Class • Member functions/methodsrepresent real object - behaviour • Member variables/data membersrepresent real object - state

9. Editor Disk Add source Code Pre-processor Disk Directives allow add contents from ext files or constants Compiler Disk Convert the high level language into object code Linker Disk Link object code to library code & create exec code Memory Load from disk into memory Loader Disk Execution, CPU executes the program CPU Creating a C++ program

10. Why Compile? English talk “Add 17 and 9 please” “Johann Strauss” I’m sorry but I don’t understand English just binary talk, 1’s and 0’s. 001010100111 011011000110 100110110011 111100100000 100000111110

11. Why Compile? C++ Talk C O M P I L E R cout<<"Enter the first number: "; cin >>Num1; cout<<"Enter the second number: "; cin >>Num2; cout<<"The two numbers added = "<<Num1 + Num2; Binary Talk Enter the first number: 17 111001101111 001010100111 011011000110 100110110011 111101011111 Enter the second number: Monitor 9 The two numbers added = 26

12. C++ Compilers • Many and varied • Sun Studio 10 Solaris, Linux • VisualAge C++ Linux • GCC Multi-platform • Microsoft Visual C++ Windows • Cygwin Linux • Dev-C++ Windows • Xcode Apple

13. Compiler Conformance • ISO International Standards Organisation • ANSI - American National Standards Institute • Standard • C++98 • C++2003 • 2005 Library Technical Report 1 • Compilers and standard library implementations should support these standards

14. Compiler Conformance • There is no C++ compiler or library today that implements the Standard perfectly

15. Standard C++ Library • Collection of classes and functions • Result of conformance to ISO standard • Incorporates what was STL • Class definitions for standard data structures • Collection of algorithms used to manipulate these and other structures

16. First Program #include <iostream> • Include contents of the header file in the program using namespace std; • cin is standard input stream object of istream class that allows input from keyboard • cout is standard output stream object, output to screen int main() • In every C++ program, function

17. First Program int aNum = 0; • variable (memory location called aNum) to hold number of type integer (int) <<stream insertion operator cout <<“Enter a number:- ”; >>stream extraction operator cin >>aNum; First program

18. Exercises • Complete Exercises 1-4 • Complete all the tasks • Restart at 3:30pm

19. Functions • Used to encapsulate data and operations • Can simplify coding • Functions for discrete tasks • Not hundreds of lines of code • Only need to know • Input data • Output data • Functions can be reused

20. Functions • Need a prototype • Tells the compiler what is coming • Return type • Function name • Parameter list (what is being passed in) voidreadChar(); intgetNumber(); doublenumDoubled(int);

21. Functions • Defining a function (no return value) voidreadChar() { char aChar; cout << "Enter a CHARACTER: " ; cin >> aChar; cout << "Character is " << aChar << endl; return; }

22. Functions • Calling a function • With no return type • readChar(); • With return type int • int myNum = 0; • myNum = readNumber(); • cout << “The integer returned is “<< myNum; Func.dev

23. Functions • Pass by Reference • Previously, pass by Value • Copy of value passed to function • Pass by Reference • Address of value passed to function FuncRef.dev

24. Exercises • Complete Exercises 5-7 • Complete all the tasks

25. Creating classes Member functions Data members Access specifiers Todays Topics • Flow Control • Sequence • Selection • if..else • switch • Repetition • while • for • do…while

26. Classes and Objects • #include <string> • stringStudent1; • intnumChar = 0; • cout << "Enter your name "; • getline(cin, Student1); • numChar = Student1.length(); • cout<<"The number of characters is: "<<numChar;

27. Classes and Objects • A class is a definition of a compound variable type • An object is an instance of that class • From a student class • Create many objects of type student • James • Sarah • Thomas • Jane • Create an instance (object) of classstudent studentJames; studentSarah;

28. Classes and Objects • Member functions • Called by objectName.functionName() James.displayName(); James.setCourseName(); James.setYears(); • Data Members (variables of object) • Member functions used to access the data members

29. Classes and Objects • Data Members • Access specifiers • private: only accessible via member functions of the class • protected: only accessed via member functions of the class and member functions of a derived class • public: can be accessed from any (non-member) function, anywhere the object is visible

30. Classes and Objects class StudentCourse { private: string courseName; public: void setName(string name) { courseName = name; } }; OxStudents.dev

31. Classes and Objects • Constructors • Default constructors, provided by compiler • Create your own & initialise data members StudentCourse (string cName) { CourseName = cName; } • Destructors • Class name preceded by tilde ~ ~StudentCourse ();

32. Classes and Objects • Separate class files for reusability • Class files with main() means the class cannot be reused. • Only have one main() function • Separate class into own file with .h suffix • Use pre-processor directive to add the file when compiled • #include “myClass.h” Constructor.dev

33. Exercises • Complete Exercises 8-13 • Complete all the tasks • Re-start 3:45pm

34. Basic Control Flow • Sequence • What we have been doing already • Selection • if…else statements • Two possible marks, 49 or 50 stored in score if(condition is true)if(score >= 50) cout<<“Passed”;cout<<“Passed”; elseelse cout<<“Failed”;cout<<“Failed”;

35. Basic Control Flow • Selection • switch multiple selection statements • Test must be constant integer value, 1, 10, ‘A’, ‘x’. Not 10.56, 5.2. switch (Test) { case1: cout<<“Number1”; break; default: cout<<“NOT Number1”; } IfSwitch.dev

36. Basic Control Flow • Repetition • The ‘for’ loop for (i = 1; i<= 5; i++) { do this statement; now do this statement; } • Note: = is an assignment <= is a relational operator == is an equality operator

37. Basic Control Flow • Repetition • while statement while(some condition is true) do the statements; while (counter < 4) { cout<<"Enter mark "; cin >> mark; total = total + mark; counter ++; }

38. Basic Control Flow • Repetition • do…while loop do { statements } while(the condition is true) • do { cout<<“Mark number " <<mark <<endl; mark ++; } while (mark <=10); DoWhile.dev

39. Exercises • Complete Exercises 14-18 • Complete all the tasks

40. Arrays Vectors Today's Topics Function Templates Pointers Interfaces

41. Arrays • Data structure containing same type of data (int,double,string,char, object) • Series of elements each containing one item of data (contiguous memory locations) • Cannot change size

42. Arrays • int inNumbers[20]; • an array of 20 integers • char inName[5]; • an array of 5 characters • double examMarks[] = {1.2, 3.9, 9.5} • initialise and set size to 3 elements of type double

43. Arrays • Adding data to arrays. double examMarks[5]; for(int i = 0; i <5; i++) { cout<<"Enter Exam Mark "<<i + 1<<" "; cin >> examMarks[i]; }

44. Arrays • Outputting data from an array for(int i = 0; i <5; i++) { cout<<"Exam Mark "<<i + 1<<"is "<< examMarks[i] <<endl; } Array.dev

45. Vectors • Container class, part of Standard Template Library, similar to arrays • Can hold objects of same type of data (int,double,string, char,object) • Can resize, grow, shrink as elements are added or removed from the end • Algorithms to manipulate data • Iterators (like pointers) to cycle through all elements in vector

46. Vectors • vector<int> vec(20); for(int i = 0; i<vec.size(); i++) vec[i] = (i); for(int i = 0; i<vec.size(); i++) { cout<< vec[i]<<" "; }

47. Vectors • Adding an extra element cout<<"Enter an Extra Value "; cin >> aNum; vec.push_back(aNum); • Print vector of 21 numbers for(int i = 0; i<vec.size(); i++) { cout<< vec[i]<<" "; }

48. Vectors VectorPushBack.dev

49. Function Templates • One function definition • Separate object code functions created, • Determined by argument • Effectively many overloaded functions • template < typename T > • Value T is a type, not a value - we don’t know that yet • T maximum( T value1, T value2, T value3 )

50. Function Templates template < typename T > T maximum( T value1, T value2, T value3 ) { T maximumValue = value1; if ( value2 > maximumValue ) maximumValue = value2; if ( value3 > maximumValue ) maximumValue = value3; return maximumValue; } FunctionTemplate.dev ArraySortVectorTEMPLATEClass