1. C++ Workshop Sujana Jyothi Dept. of Computer Science

2. Week Outline Monday – Introduction to C++ Basics Tuesday – I/O and Functions Wednesday – Arrays and Pointers Thursday – Strings, Structures and Classes Friday – File I/O, Exceptional Handling

3. Day Outline Lectures : 9:30 – 11:30 Assignment Lectures : 14:30 – 16:30

4. Introduction to Basic Procedural Programming Try to simulate compilation and execution in your head Try different variations on a theme - simply edit the examples Easiest way to learn programming is to experiment The computer is a laboratory If you don’t know something then write a program to give you the answer … if you can Otherwise, try looking in a book (or on the web) You can always ask someone (doesn’t have to be me)

5. Practical Info Work on the C:\ disk can only be saved in the temp folder. WARNING!!! If you leave your work in the temp folder and then log out… it will be lost! Therefore save all of your work to your personal X:\ disk or on some USB storage

6. C++ Resources Textbooks here in the lab. Online resources: 1.http://en.wikipedia.org/wiki/C++_standard_libraryhttp://en.wikipedia.org/wiki/C++_standard_library 2.http://www.cplusplus.com/http://www.cplusplus.com/ 3.http://www.sgi.com/tech/stl /http://www.sgi.com/tech/stl /

7. C++ Intro We need to learn the language, start with the syntax! Any Java programmers will be fine, C programmers will survive too! Lets get started….

8. Workstation We will be using Visual Studio 2005 When you first run Visual Studio, it asks you what kind of work you intend to do with it. Choose the option that says you'll be doing "Visual C++ development," which will configure the application to work best for doing C++ work.

9. First Program // Example 1 /* Sujana Jyothi C++ Workshop */ #include “stdafx.h” #include using namespace std; int main() { cout<<"Hello World"<<endl; } When namespace is not used: std::cout<<"Hello World"<<std::endl;

10. Command Line Arguments // Example 2 #include "stdafx.h" #include using namespace std; int main (int argc, char* argv[]) { cout<<"Hello World"<<endl; if (argc == 1) cout << "No arguments given" << endl; else for (int i = 1; i < argc; i++) cout << i<< " the argument is "<< argv[i] << "\n"; }

11. execution Compilation & Execution Compile - Go to the Build menu and select Build Solution (or press F7 as a shortcut). The output of the compilation process should appear in the Output area of the VS window. Run - You can run it with or without debugging.  select ‘Start Debugging’ from the Debug menu or press F5  select ‘Start WO Debugging’ from Debug menu or press ‘ctrl+F5’ Command prompt: Start -> All Programs -> Microsoft Visual Studio 2005 -> Visual Studio Tools -> Visual Studio 2005 Command Prompt. At the command prompt, type “notepad filename.cpp” and press Enter. type cl /EHsc filename.cpp type filename Enables c++ Exception handling

12. Example1 Variations – What will happen in each case /* Example 1A CS613 C++ Code */ int main ()// does nothing!! {return 0;} /* Example 1B CS613 C++ Code */ int main () {} /* Example 1C CS613 C++ Code */ main ()// does nothing!! {return 0;} // Example 1D int main () {return 7} // Example 1E int main (){return 0.7;;} // Example 1F float main (){return 0.7;}

13. Rules to learn variables identifiers types values constants keywords

14. C++ Data Types Structured array struct union class Address pointer reference Simple IntegralFloating char short int long enum float double long double

15. Typical size of data types Type Number of Bytes char1 short (short int) 2 int 4 unsigned int4 enum2 long (long int) 4 float4 double 8 long double12

16. Finding size of data type - system dependent results sizeofUse sizeof to find the size of a type e.g. std::cout << sizeof(int)

17. Enumerated types: enum Used to define constant values enum days { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday } yesterday, today; days tomorrow; QUESTION: what are the values of Tuesday, today, tomorrow, yesterday ? Default values may be overridden in the enum list.

18. Boolean type C++ has a built-in logical or Boolean type #include int main (){ bool flag = true; std::cout << flag<< std::endl<<!flag} This outputs: 1 0

19. Variation - Booleans are really integers? // #include int main (){ bool flag1 = 100, flag2 = false, flag3; std::cout << flag1<< std::endl<<flag2<< std::endl<<flag3;} This outputs: 1 0 122 true is any non- zero int false is zero true is output as 1 false is output as 0 This was not initialised

20. Giving a value to a variable In your program you can assign (give) a value to the variable by using the assignment operator = Age_Of_Dog = 12; or by another standard method, such as std::cout << “How old is your dog?”; std::cin >> Age_Of_Dog;

21. What is a Named Constant? A named constant is a location in memory which we can refer to by an identifier, and in which a data value that cannot be changed is stored. VALID CONSTANT DECLARATIONS const char STAR = ‘*’ ; const float PI = 3.14159 ; const int MAX_SIZE = 50 ;

22. keywords: words reserved to C++ bool, true, false, char, float, int, unsigned, double, long if, else, for, while, switch, case, break, class, public, private, protected, new, delete, template, this, virtual, try, catch, throw. Note: there are many more … you may see them in the examples that follow

23. Example 6: prefix and postfix // #include int main (){ int x =3, y=3; std::cout << ++x << std::endl; std::cout << y++ << std::endl;} Output: 4 3 ++ (prefix) is a unary operator ++ (postfix) is a unary operator << is a binary operator

24. Example 7: a C+ ternary operator // Example 7 #include int main (){ int x =3, y=4; std::cout <<"The max. of x and y is: " y?x:y); } The max. of x and y is: 4 expression1?expression2:expression3 Output: Means: if expression1 then expression2 else expression3

25. Program with Three Functions // #include // declares these 2 functions int Square ( int ); int Cube ( int ) ; int main ( void ){ std::cout << "The square of 27 is " << Square (27) << std::endl ;// function call std::cout << "The cube of 27 is " << Cube (27) << std::endl ;// function call return 0 ; } int Square ( int n ){return n * n ;} int Cube ( int n ){return n * n * n ;} The square of 27 is 729 The cube of 27 is 19683 Output:

26. Precedence of Some C++ Operators Precedence OperatorDescription Higher ( )Function call +Positive - Negative *Multiplication / Division %Modulus (remainder) +Addition - Subtraction Lower = Assignment NOTE: Write some programs to test your understanding of precedence

27. Type Casting is Explicit Conversion of Type // Example #include int main ( void ){ std::cout << "int(4.8) ="<<int(4.8)<<std::endl; std::cout << "float(5) ="<<float(5)<<std::endl; std::cout <<”float(2/4)="<<float(2/4)<<std::endl; std::cout<<"float(2)/float(4) ="<<float(2)/float(4)<<std::endl; } int(4.8) =4 float(5) =5 float(2/4)=0 float(2)/float(4)=0.5 Output: Output of float may look like an int

28. Parts of a Function Every function has 2 parts int main (void) { return 0; } signature body

29. HEADER FILE FUNCTION EXAMPLE VALUE OF CALL std::fabs(x) std::fabs(-6.4) 6.4 std::pow(x,y) std::pow(2.0,3.0) 8.0 std::sqrt(x) std::sqrt(100.0) 10.0 std::setprecision(n) std::setprecision(3) std::log(x) std::log(2.0) 0.693147 std::sqrt(2.0) 1.41421 std::abs(i)std::abs(-6) 6

30. C++ I/O Basics 30 I/O - Input/Output is one of the first aspects of programming that needs to be mastered: formatting whitespace structured inputs - getting data into the correct internal form However, do not fall into the beginner’s traps: brilliant I/O with incorrect functionality thinking functionality is wrong because I/O is too complicated to get right forgetting that random tests are often better than user dependent I/O

31. Whitespace Characters Include... blanks tabs‘\t’ end-of-line (newline) characters ‘\n’ The newline character is created by hitting Enter or Return at the keyboard, or by using the manipulator endl or “\n” in a program. E.g std::cout << std::endl; std::cout << “\n”;