1. A First Book of C++ Chapter 1 Getting Started

2. Objectives In this chapter, you will learn about: –Introduction to Programming –Function and Class Names –The cout Object –Programming Style –Common Programming Errors –Software Development A First Book of C++ 4th Edition2

3. Introduction to Programming Computer program –Data and instructions used to operate a computer Programming –Writing computer program in a language that the computer can respond to and that other programmers can understand Programming language –Set of instructions, data, and rules used to construct a program High-level languages Low-level languages A First Book of C++ 4th Edition3

4. Introduction to Programming (cont’d.) Procedural language –Instructions are used to create self-contained units (procedures) –Procedures accept data as input and transform data to produce a specific result as an output –Initially, high-level programming languages were predominately procedural A First Book of C++ 4th Edition4

5. Introduction to Programming (cont’d.) A First Book of C++ 4th Edition5

6. Introduction to Programming (cont’d.) Object-oriented languages –Program must define objects that it is manipulating –Such definitions include: The general characteristics of objects Specific operations to manipulate objects C++ is an object-oriented language –Has procedures and objects –Supports code reuse A First Book of C++ 4th Edition6

7. Introduction to Programming (cont’d.) C++ began as extension to C –C is a procedural language developed in the 1970s at AT&T Bell Laboratories In early 1980s, Bjarne Stroustrup (also at AT&T) used his background in simulation languages to develop C++ Object-orientation and other procedural improvements were combined with existing C language features to form C++ A First Book of C++ 4th Edition7

8. Algorithms and Procedures Before writing a program, a programmer must clearly understand: –What data is to be used –The desired result –The procedure needed to produce this result The procedure is referred to as an algorithm –Step-by-step sequence of instructions describing how to perform a computation A First Book of C++ 4th Edition8

9. Algorithms and Procedures (cont’d.) Assume that a program must calculate the sum of all whole numbers from 1 through 100 A computer: –Cannot respond to heuristic command: “Add the numbers from 1 - 100” –Is an algorithm-responding machine and not a heuristic-responding machine Several methods or algorithms can be used to find the required sum A First Book of C++ 4th Edition9

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11. A First Book of C++ 4th Edition11

12. A First Book of C++ 4th Edition12

13. A First Book of C++ 4th Edition13

14. Classes and Objects Data object –Set of values packaged as single unit Class –Set of objects with similar attributes General concept of object-oriented programming is difference between an object and the larger set of which it is a member (class) A red, Ford Taurus sedan is an instance, or object, of a general class of automobiles A First Book of C++ 4th Edition14

15. Program Translation C++ source program –Set of instructions written in C++ language Machine language –Internal computer language –Consists of a series of 1s and 0s Source program cannot be executed until it is translated into machine language –Interpreted language translates one statement at a time (BASIC – Perl) –Compiled language translates all statements together A First Book of C++ 4th Edition15

16. Program Translation (cont'd.) A First Book of C++ 4th Edition16

17. Program Translation (cont'd.) A First Book of C++ 4th Edition17

18. Function and Class Names Modular programs –Segments arranged in logical order to form an integrated unit Module –Segments of modular program Function: Name of a C++ procedure –Composed of sequence of C++ instructions –Function interface is its inputs and results –Method of converting input to results is encapsulated and hidden within function A First Book of C++ 4th Edition18

19. Function and Class Names (cont'd.) A First Book of C++ 4th Edition19

20. Function and Class Names (cont'd.) A First Book of C++ 4th Edition20

21. Function and Class Names (cont'd.) An important requirement for designing a good function or class is giving it a name that conveys some idea of what the function or class does. The names allowed for functions and classes are also used to name other elements of the C++ language and are collectively referred to as identifiers. Identifiers can be made up of any combination of letters, digits, and underscores ( _ ) selected according to the following rules: A First Book of C++ 4th Edition21

22. Function and Class Names (cont'd.) Identifiers –Names that convey an idea of the purpose of function or class Identifier composition rules –First character must be a letter or underscore –Only letter, digit, or underscore may follow –Blank spaces aren’t allowed –Separate words in a multiple-word identifier are indicated by capitalizing the first letter of one or more of the words –Should be a mnemonic – Maximum of 1024 characters –Cannot be one of the keywords listed in Table 1.1 A First Book of C++ 4th Edition22

23. Function and Class Names (cont'd.) A First Book of C++ 4th Edition23

24. Function and Class Names (cont'd.) Examples of valid identifiers: grosspaytaxCalc addNumsdegToRad multByTwo salesTax netPaybessel A First Book of C++ 4th Edition24

25. Function and Class Names (cont'd.) Examples of invalid identifiers: 4ab3(begins with a number) e*6(contains a special character) while(is a keyword) A First Book of C++ 4th Edition25

26. Function and Class Names (cont'd.) In addition to conforming to C++’s identifier rules, a C++ function name must always be followed by parentheses. Function names can also consist of mixed uppercase and lowercase letters, as in locateMaximum(). C++ is a case-sensitive language, meaning the compiler distinguishes between uppercase and lowercase letters. Therefore, in C++, the names TOTAL, total, and TotaL are three different identifiers. A First Book of C++ 4th Edition26

27. The main() Function Each C+ program must have one and only one function named main Called a driver function because it drives the other modules A First Book of C++ 4th Edition27

28. The main() Function (cont'd.) A First Book of C++ 4th Edition28

29. The main() Function (cont'd.) First line of function is called header line –What type of data, if any, is returned from function –The name of function –What type of data, if any, is sent into function Data transmitted into function at runtime are referred to as arguments of function A First Book of C++ 4th Edition29

30. The main() Function (cont'd.) A First Book of C++ 4th Edition30

31. The cout Object The cout object sends data to the standard output display device –The display device is usually a video screen –Name derived from Console OUTput and pronounced “see out” Data is passed to cout by the insertion symbol – cout << “Hello there, World!”; A First Book of C++ 4th Edition31

32. The cout Object (cont’d.) A First Book of C++ 4th Edition32

33. The cout Object (cont’d.) Preprocessor command –Performs an action before the compiler translates source code to machine code –Example: #include –Causes the iostream file to be inserted wherever the #include command appears iostream is part of the C++ standard library –Included in iostream are two important classes: istream : Declarations and methods for data input ostream : Declarations and methods for data output A First Book of C++ 4th Edition33

34. The cout Object (cont’d.) Namespace –File accessed by compiler when looking for prewritten classes or functions Sample namespace statement: –using namespace std; –iostream contained in a namespace called std –Compiler uses iostream ’s cout object from std whenever cout is referenced A First Book of C++ 4th Edition34

35. The cout Object (cont’d.) A First Book of C++ 4th Edition35

36. The cout Object (cont’d.) Newline escape sequence –Instructs the display device to move to a new line –Caused when the characters backslash \ and n are used together –Backslash provides an “escape” from the normal interpretation of the character that follows Newline escape sequences can be placed anywhere within a message to cout A First Book of C++ 4th Edition36

37. The cout Object (cont’d.) A First Book of C++ 4th Edition37

38. Programming Style Every C++ program must contain one and only one main() function –Statements included within braces { } C++ allows flexibility in format for the word main, the parentheses ( ), and braces { } –More than one statement can be put on line –One statement can be written across lines Use formatting for clarity and ease of program reading A First Book of C++ 4th Edition38

39. Programming Style (cont’d.) Function name starts in column 1 –Name and parentheses on their own line Opening brace of function body on next line –Aligned with first letter of function name Closing brace is last line of function –Aligned with opening brace Standard form highlights the function as a unit A First Book of C++ 4th Edition39

40. Programming Style (cont’d.) Within function, indent statements 2-3 spaces –Creates uniform look for similar statement groups –Good programming practice Final program form should be consistent –Proper format improves program readability and understandability A First Book of C++ 4th Edition40

41. Comments Explanatory remarks written within program –Clarify purpose of the program –Describe objective of a group of statements –Explain function of a single line of code Computer ignores all comments –Comments exist only for convenience of reader A well-constructed program should be readable and understandable –Comments help explain unclear components A First Book of C++ 4th Edition41

42. Comments (cont’d.) Line comment –Begins with two slashes( // ) and continues to the end of the line –Can be written on line by itself or at the end of line that contains program code // this is a line comment Block comment –Multiple-line comment begins with the symbols /* and ends with the symbols */ /* This is a block comment that spans three lines */ A First Book of C++ 4th Edition42

43. Common Programming Errors Omitting parentheses after main() Omitting or incorrectly typing the opening brace { –Opening brace signifies start of function body Omitting or incorrectly typing the closing brace } –Closing brace signifies end of function Omitting the semicolon at the end of each statement Adding a semicolon after the #include preprocessor command A First Book of C++ 4th Edition43

44. Common Programming Errors (cont'd.) Misspelling the name of an object or function –Example: Typing cot instead of cout Forgetting to close a string sent to cout with a double-quote symbol Forgetting \n to indicate a new line A First Book of C++ 4th Edition44

45. Summary A C++ program consists of one or more modules –One module must be the function main() –main() is starting point of C++ program The simplest C++ program has the form: #include using namespaces std; int main() { program statements; return 0; } A First Book of C++ 4th Edition45

46. Summary (cont'd.) C++ statements are terminated by a semicolon Standard library contains many functions and classes –Standard Library provided with C++ compiler –Includes for input and output cout object displays text or numeric results –Stream of characters is sent to cout by: Enclosing characters in double quotes Using the insertion (“put to”) operator, << A First Book of C++ 4th Edition46

47. Chapter Supplement: Software Development Professional software developers use the software development procedure –For understanding the problem to be solved and for creating an effective, suitable software solution Consists of three overlapping phases: –Development and design –Documentation –Maintenance A First Book of C++ 4th Edition47

48. Phase I: Development and Design A First Book of C++ 4th Edition48

49. Phase II: Documentation Every problem solution has five main documents: –Program description –Algorithm development and changes –Well-commented program listing –Sample test runs –Users’ manual A First Book of C++ 4th Edition49

50. Phase III: Maintenance Phase is concerned with: –Ongoing correction of problems –Revisions to meet changing needs –Addition of new features A First Book of C++ 4th Edition50

51. Chapter Supplement: Backup Not part of the formal design process Keeping backup copies of the program at each step of the programming and debugging process is critical With backup copies, you can recover the last stage of work with little effort A First Book of C++ 4th Edition51