C++ Programming Fundamentals: Header Files, Comments, & Operators

1. Beginning with C++ Dr. Bhargavi Dept of CS CHRIST 9426669020

2. Header files • Comments // or /* comments */ • Output Operator, bitwise shift left operator cout<<“print it”<<string; • Assert.h = macros and debugging • Ctype.h = test properties of function prototype • Float.h = float size limit • Limits.h = integral size limits • Math.h = math library function • Stdio.h = standard input output • Stdlib.h = convert number to text, etc • String.h = c-style string processing • Time.h = time land date manipulation • Iostream.h = standard input output functions • Iomanip.h = formatting streams of data • Fstream.h = input to file and output from file functions

3. New header files • Utility = has classes and functions used by other header files • Vector, list, deque, queue, set, map, stack, bitset = standard containers • Functionals = algorithms of standard library • Memory = allocate memory • Iterator = manipulates data • Algorithms = manipulate data in standard library containers • Exception, stdexcept = exception handling • String = class string definition • Sstream = input from string to memory and output to string in memory • Locale = stream processing for different language • Limits = define numerical data type limits • Typeinfo = run time type identification

4. Namespace • Defines scope of identifiers used in a program. • Std is namespace according to ANSI C++ standards • It brings all the identifiers defined in “std” to current global scope. • ‘using’ and ‘namespace’ are keywords of C++.

5. Return type of Main() • Is Integer • Therefore, every program has to end with return 0. • Default return type of all the functions in C++ is ‘int’. • Consequence? • Warning or error. • Eg. Average of Two numbers • Average of Ten numbers

6. Variables • Can be declared anywhere in the program. • Must be declared before used.

7. Output operator cascading • Cout<<“Print variable:”; • Cout<<string; • Cascading can be done: • Cout<<“Print Variable:”<<num1<<endl; • C-out • Called standard output stream • Represents screen • We can redirect output to other devices or memory in the form of file. • << is called insertion operator • << is bitwise left shift operator • Operator overloading can be done on it for additional functionality • Works such as printf();

8. Input operator cascading • Cin>>number1; • C-in • Operator >> is known as extraction or get from operator. • Similar to scanf() operation • >> operator can be overloaded. • Eg. cin>>num1; • cin>>num2;

9. Cascading i/0 operators • Input and output operators can be cascaded. • Eg: • Cout<<“Sum=”<<sum<<“\n”; • Cout<<“Sum”<<sum<<“\n”<< “ ,Average=”<<average<<“\n”; • Output: Sum=14, Average=17;

10. Class • Major features of C++ is a class. • Binding together data and functions • Is a user defined datatype • Eg. • 1. use of class • 2. class box

11. Structure of c++ Program INCLUDE FILES CLASS DECLARATION MEMBER FUNCTIONS DEFINITION MAIN FUNCTION PROGRAM

12. END OF CHAPTER 2 THANK YOU

13. Tokens,expressions &control structures Dr. Bhargavi Dept of CS CHRIST 9426669020

14. tokens • Definition? • The smallest individual units in the program. • How many tokens are there in C++? • 5. • Which are they? • Keywords, Identifiers, Constant, Strings Operators.

15. keywords

16. Identifiers and constants • Identifier definition? • It refers to the names of variables, functions, arrays, classes, etc. • Rules? • Only alphabetic characters, digits and underscores • Cannot start with digit • Considers upper and lower case Distict • Keywords cannot be identifiers • Constants definition? • Fixed values that do not change during execution. • Literal constants do not have memory locations. • What is wchar_t? • Wide character literal introduced by ANSI C++. • Intended for character sets that do not fit a character into single byte. • It begins with letter L.

17. Basic data types

18. Size and range of data types

19. Storage classes

20. Dynamic initialization of variables • C++ allows initialization of variables at run time. • Eg. int n = strlen(string); • Eg. float area = 3.14 * rad * rad; • Eg. float average = sum/I;

21. Reference variables • What is this? • It’s the alias (alternative name) for previously defined variable. • One memory location, two or more names. • Condition? • Must be initialized at the time of declaration. • Represented by? • & but, it is not an address operator. • Use? • Manipulation of objects by reference. Avoids copying and pasting of object variables to and fro. • Eg. total may have an alias as sum and can refer to same variable. • Syntax: data-type & reference-name = variable-name • Eg. float total = 100; • float & sum = total; • Eg. 3_ReferenceVariable.cpp

22. Operators in c++

23. Scope resolution operator • C++ is also block structured language. • Use? • Variables with same name can have different meaning in different blocks. • Even memory location is different even though the name is same in the same program. • Limitation of C: global variable cannot be accessed and manipulated within the local blocks. • Resolved by C++? • Yes. • How? • Using scope resolution operator. • Eg. Check 3_ScopeResolOpr.cpp • Detect output of 3_ScopeResolOprEx2.cpp • Also check 3_1ScopeResolutionOperator.cpp

24. Member dereferencing operator • Can we access class members using pointers? • Yes. • How? • Using 3 pointer to member operators. • Detailed discussion will be done during the chapter of pointers.

25. Memory management operator • C has the concept of malloc(), calloc() and free(). • Although C++ supports these function, in addition, also support unary operators for doing that task in easy and better way. • How? • Using new and delete. • Also called free store operators. • The life time of the operators are in direct control of the programmers. • Syntax: pointer-variable = new data-type(value); • Syntax: delete pointer-variable; • For array: • Syntax: pointer-variable = new data-type[size]; • Syntax: delete [size]pointer-variable; • Eg. 3_new-delete.cpp • Eg. 3_3UseOfBad_AllocException.cpp

26. manipulators • In detail we will study in chapter of streams and i/o manipulators. • Just check the output of the program as of now. • Eg. 3_manipulators.cpp

27. Self study • 1. explicit type casting • 2. control structures of • If • Switch • Do-while • While • For

28. END OF CHAPTER 3 THANK YOU

29. Functions in C++ Dr. Bhargavi Dept of CS CHRIST 9426669020

30. Function prototype • It provides three information to compilers called template. • Which 3 information? • Name of function, number and type of arguments and type of return values. • Any violation in match of these three information results to compilation error. • Form: type function-name (argument-list); • Eg. float vol(int x, float y, float z) { //function body } • Call statements: float cube = vol(b1,w1,h1); • Eg: 4_FunctionPrototype.cpp

31. Function arguments • Call by value: passing arguments to a function copies the actual value of an argument into the formal parameter of the function. Eg. 4_CallByValue.cpp • Call by pointer: passing arguments to a function copies the address of an argument into the formal parameter. Eg. 4_CallByPointer.cpp • Call by reference: passing arguments to a function copies the reference of an argument into the formal parameter. Eg. 4_CallByReference.cpp • Return by reference: When a function returns a reference, it returns an implicit pointer to its return value. Eg. 4_ReturnByReference.cpp

32. Inline function • What is the objective of using function? • To save memory space. • But, memory space is saved at the cost execution time due to execution of long function body, pushing arguments to stack, jumping to and fro function, returning to calling function. • Effect is minimum when applications are small, but affects execution time worst when application grows. • Problem? • Yes. Solution? • 1. Macro. • But, drawback is being not functions, compile time errors are not checked. • 2. Inline Function.

33. Inline function • Definition: The function that is expanded in line when it is invoked. • How it works? • Compiler replaces function call with corresponding function code. • What is the effect? • Makes program run faster. Execution time reduces. • Similar to macros expansion? • Yes. Then what is the advantage. • Error checking at compile time is done. • If its so good, y can’t we make all functions inline? • If functions are large, inline effect diminish.

34. Inline expansion may not work in situations: • Functions returning values • Functions with loops, switch or goto stmts. • Functions containing static variables • Functions that are recursive • Eg. 4_1InlineFunctions.cpp

35. Default arguments • Can you call a function with arguments without providing the arguments? • Yes or No? • C++ provides this facility by Default Arguments. We can call a function without specifying all its arguments. • How? • Provide default values to arguments. • Advantage? • No need to specify arguments at each function call. • Add new parameters to function without making call statements complex. • Also allows to override the default value. • Used to combine similar funtions. • Remember. • Only trailing arguments can have default values. • Eg. 4_2DefultArgument.cpp

36. Const arguments • Can arguments be constant? • Yes. • How. • Eg. intstrlen(const char *p); • Eg. length(const string &s); • Compiler is told by keyword ‘const’ that function should not modify the argument. • Eg. 4_constant.cpp

37. Function overloading • Define overloading. • Use of same thing for different purposes. • Another name? • Function Polymorphism. • We can design a family of function with same name but different argument list. • Calculating area depending on shape. • Eg. 4_5FunctionOverloading.cpp

38. END OF CHAPTER 4 THANK YOU