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Chapter 2

Chapter 2. Creating a C++ Program. Elements of a C++ Program. Four basic ways of structuring a program Sequencing Selection Looping Sub-program. Basics. All programs must have at least one function We will learn to write many functions

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Chapter 2

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  1. Chapter 2 Creating a C++ Program

  2. Elements of a C++ Program • Four basic ways of structuring a program • Sequencing • Selection • Looping • Sub-program

  3. Basics • All programs must have at least one function • We will learn to write many functions • We will build more complex programs from simple functions

  4. Parts of the Programs • Identifiers • A name associated with a function or data object • It is used to reference that function or data object

  5. How to Name Identifiers • Must start with a letter or underscore • Followed by a letter, number or underscores • Cannot be a reserved word

  6. Quiz • Write true if the identifier’s name good and false otherwise: _Fred 3DArray R2D2 Silly_Name Good Name x BadName Id3nt1f13r Bonus: int const_cast

  7. Examples of Reserved Words • int • double • const • return • bool • if • while • for

  8. Data and Data Types • Data type • Determines how the data is represented in the computer and how the computer can operate on it • Data • What all computers use to compute

  9. Data Types • Two Kinds • Built-in • User Defined • Example of Built-in • int • double • bool • char

  10. char Data Type • Any single alphanumeric character • Example • ‘A’ • ‘a’ • ‘B’ • ‘1’ • ‘^’

  11. string Data Type • Not a built-in type • Any sequence of characters • Example • “Dave” “C++” “ 9 “ • Strings cannot span more than one line • Null String • “”

  12. Naming Elements • Use a Declaration • int empNum; • Variables • A location in memory, referenced by an identifier, that contains a data value that can be changed • Constants • A location in memory, referenced by an identifier, that contains a data value that cannot be changed

  13. Examples • int Counter; • double taxRate, Percent; • const char MIDDLEINITIAL = ‘P’; • const bool NOTTRUE = “false”;

  14. Executable Statements • Assignment Statements • lastName = “Roszak”; • Output Statements • cout << “Hello World”;

  15. Non-executable Statements • Comments • //This is how you indicate a comment • /*Or you can do it this way*/

  16. Blocks • Groups of lines that are to be grouped together between curly braces • Example • int main() { cout << “Hello World; }

  17. Pre-processor • Before the program is compiled, a program called a pre-processor parsers the code looking for directives; things to do • Example • #include <iostream> • #ifndef • #endif

  18. Introduction to Namespaces int main() { cout << “Happy Birthday” << endl; return 0; }

  19. More Namespaces #include <iostream> int main() { cout << “Happy Birthday” << endl; return 0; }

  20. Still More #include <iostream> int main() { std::cout << “Happy Birthday” << std::endl; return 0; }

  21. Yet More #include <iostream> using std::cout; using std::endl; int main() { cout << “Happy Birthday” << endl; return 0; }

  22. One More #include <iostream> using namespace std; int main() { cout << “Happy Birthday” << endl; return 0; }

  23. More Output • What will the following lines produce? • cout << “Hi there. “ << endl; • cout << endl; • cout <<“What are you doing?” << endl;

  24. More Output • What will these produce? • cout << “Hi there. “ << endl << endl <<“What are you doing?” << endl; • How about these? • cout <<“Hi there. \n\nWhat are you doing?\n”

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